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FAQs on Otocinclus 1

Related Articles: OtocinclusLoricariids

Related Catfish FAQs: Otocinclus 2, & FAQs on: Otocinclus Identification, Otocinclus Behavior, Otocinclus Compatibility, Otocinclus Selection, Otocinclus Systems, Otocinclus Feeding, Otocinclus Health, Otocinclus Reproduction, & Suckermouth Catfishes of South and Central America, Loricariid Identification, Loricariid Behavior, Loricariid Compatibility, Loricariid Selection, Loricariid Systems, Loricariid Feeding, Loricariid Reproduction, Loricariid Disease, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction Algae Eaters

Otocinclus affinis Steindachner 1877, the Golden Otocinclus

Oto loses colour Hi, We have a sick Oto which has suddenly lost its pigmentation and is looking a sickly grey. It is swims weakly, sometimes floating at the surface and drifting in the current. Otherwise its body, fins, etc. look in good condition. Can you suggest any remedy or is this something to do with the tank conditions? We have a 180-litre (40 gallon) community tank with 9 guppies, 3 minnows, a Pleco and 5 Otos altogether. It has some live and plastic plants, a couple of logs and a small rock pile (slate), i.e. there is a relatively large surface area available for the Otos to graze on. It has been set up for about 3 months, but, about 3 weeks ago, we had problems with water quality, fungus and white spot. These were successfully treated with 10% water changes every day and ESHA 2000 and EXIT. Treatment finished 7 days ago. Current conditions pH = 7.8, KH = 6°, GH = 12°. Ammonia, nitrite and nitrate levels all low. We have isolated the sick Oto. Grateful for your advice. Regards, Quentin <Hello Quentin. Let me start by making a general statement about Otocinclus: they are extremely difficult to maintain, and the vast majority die soon after import. The problem is that they feed on really only a single thing -- aufwuchs, a combination of green (and exclusively green!) algae together with the tiny invertebrates that live within that green algae 'biofilm'. Unless you have an established aquarium of large size with very strong lighting (2+ watts per gallon) so that green algae can flourish, it is exceedingly unlikely your Otocinclus will be getting enough to eat. How many months it is before they die is variable, but starve they will unless ample substitutes are provided. Algae wafers can work, but Otocinclus find it difficult to compete with other fish, and the fact you have other algae-eaters, specifically guppies and Plecs, makes this point critical. For this reason, I simply don't recommend them as community fish. Furthermore, while water chemistry itself isn't all that important, temperature and water quality are very important. Most people keep their tanks far too warm for Otocinclus, which come from cool, fast-flowing streams and want something in the 20-25 degrees C range rather than the usual 24-28 degrees C most people maintain standard community tropicals at. In other words, a near-subtropical, fast-water tank with things like White Cloud Mountain Minnows and Danios is much closer to what they want than a standard Amazon community aquarium. You also mention ammonia and nitrite levels as being "low" -- but be under no illusions here, Otocinclus MUST have zero levels of both. If you can detect either in your tank, it is simply not suitable for Otocinclus. In all likelihood the sickly specimen will be dead within a few days, so treatment here is irrelevant. Optimizing water quality, lowering water temperature, providing ample green algae and suitable invertebrates would all be things you could do to help the isolated fish, but that's about it. For the rest, you need to ensure your aquarium satisfies the demands outlined above. Hope this helps, Neale.>

Re: Oto loses colour 7/6/08 Neale, Many thanks for your helpful advice. The Oto has now died, sadly. However, we will develop the tank environment to make it better suited to Otocinclus. They are an entertaining fish to watch. <Yes they are. In the right tank, they can be great fun. In the wrong tank though... My most recent run-in with this species was a disaster, some of the Otocinclus deciding to graze on the mucous of some large benthic gobies. They have a reputation for attacking big, slow moving fish such as Discus and Angelfish. On the other hand, aquarists like Takashi Amano make much use of Otocinclus in planted aquaria, usually alongside Caridina shrimps as a superb combination for green algae control in brightly lit aquaria.> Thanks again. Your website is a mine of information and a great support to the budding enthusiasts in our family. Regards, Quentin <We're happy to help, and thanks for the kind words. Cheers, Neale.>

How to keep bacteria alive in a fishless tank?  4/24/08 Hello Neale, <Giuseppe,> hope you and your tanks are doing well. <Yep, we're all just fine; thanks for asking!> I have 2 unrelated questions. 1) I will be on vacation for 2 weeks in June and I was wondering if the good bacteria would starve to death in a tank without fish. By then I will have all my fish in the 46-gal, but I would like to keep the established 10-gal running to try breeding when I'm back. Again my question is whether or not the good bacteria would starve in these 2 weeks or not and what could be a solution. Maybe I should leave 1 or 2 Otocinclus and they would eat the algae in the tank? <Otocinclus aren't my favourite fish in the trade because their survival record is so poor. But certainly some hardy algae eater, like an Ancistrus or Hemiloricaria whiptail, could be left in the 10 gallon tank for a couple of weeks with a bit of carrot for grazing but otherwise left to fend for himself. Alternatively, just stick a small frozen prawn in the tank and let it rot away. Remove when you get back, obviously. Yet another option would be a plain "holiday block" of the type often sold for Goldfish and the like. These are basically lumps of limestone that dissolve away, releasing flakes of food. Again, the food will rot, producing ammonia. The bacteria couldn't care less where the ammonia comes from.> 2) How should I feed Otocinclus? I used to have 1 in the 10-gal tank and he did great for 1 year without feeding anything. When I moved the fish to the 46-gal it died after a couple of weeks, probably because there was no algae in the tank. When I'll be on vacation for 2 weeks I will use an automatic feeder loaded with flakes or mini pallets, which the Otocinclus wouldn't eat. Do you think the poor guy would starve? <Otocinclus are very difficult to feed. They almost entirely eat "aufwuchs", the combination of green algae and micro-invertebrates that encrust surfaces in bright, clear waters. They are opportunistic to some degree though -- most notoriously eating the mucous from slow moving fish -- but still, getting enough food into them within a community setting can be very hard. They do best (perhaps only do well) in large tanks with established algae "turfs" on the rocks and plants where they can feed continuously, supplementing that diet with bloodworms, algae wafers, and so on. I'd tend to avoid in favour of hardier, more adaptable Loricariidae, of which there are many.> Thanks, Giuseppe <Cheers, Neale.>

What is the best live plant for Otocinclus?  4/19/08 What is the best type of live plant for Otocinclus? I have two tanks, one 30 gallon and one 10 gallon. I just added two Otocinclus to the 10 gallon, which is 4 months old and has 8 molly fry, born two months ago. (As they grow, I plan to move them to a bigger tank and only keep 2 mollies in the 10 gallon with the Otos.) I appreciate your site. Thank you! <Otocinclus spp. couldn't care less about plants, so use whatever you want. What Otocinclus need is green algae (not diatoms and not hair algae). So provided you have 2 Watts per gallon upwards, plus lots of surfaces to grow green algae (rocks, plastic plants, etc.) they will be happy. Otocinclus spp. are not compatible with Mollies; their water chemistry requirements are entirely different. Specifically, Mollies more often than not need salt to do well and definitely need hard, basic water conditions. Salt will stress the Otocinclus, which need not-too-warm, oxygen rich water that is soft and slightly acidic. There's no overlap really between what the two species need to do well in the long term. Otocinclus are extremely demanding, difficult fish, and the vast majority of specimens die within months of import. Good luck, Neale.>

Re: What is the best live plant for Otocinclus?  4/19/08 Thank you for your help. I will separate my Otos and my mollies. I am very new at this, and I obviously have a lot to learn. :) <Glad to help. There is indeed lots to learn, so buying a book before buying a fish is always good advice. Remember, the guys in the pet store mostly want to make sales! Good luck! Neale.>

Question for Neale about TFH article, 10 gal. stkg.  Otos f'    01/13/2008 Neale, <Hello Evan,> I read your article in the TFH about 10 Gallon stocking. I was wondering if you had a reason for not mentioning Otocinclus along with the Corydoras. Is there a specific reason to not add the Otos to a 10G tank or were you just limiting yourself to keep the article concise? <Yes, there was a specific reason for leaving them off: Otocinclus spp. have an abysmal track record in aquaria generally, the VAST majority dying within a few months of introduction. I would never recommend them to anyone without several years of experience, and even then, only when placed in a mature tank (lots of green algae/aufwuchs) and excellent filtration. This pretty much rules out the average 10 gallon tank received as Christmas present, which was the focus of the article. If you want an algae-eater, get cherry shrimps; if you want a catfish, get Corydoras hastatus or some other Dwarf Corydoras. Both these will prosper without anything more than an "average" level of care, i.e., water changes, proper food, etc.> I ask because I have a 10G with 9 Glowlight Tetras to which I would like to add 3 or 4 Otos (as soon as LFS orders some). <Think very carefully about this, and only if you have LOTS of green algae. Otocinclus really don't eat anything much besides green algae and the microorganisms therein. Brown algae, blue-green algae, etc. aren't substitutes! To get green algae growing, you'll need 2 Watts of light per gallon, at least. There needs to be a "turf" of green fuzzy algae on the plants and rocks. THAT'S what these little catfish eat. On top of that, you need plenty of water flow (at least 4x the volume of the tank in turnover per hour, and ideally 6+) and above-average oxygenation. Nitrates need to be close to zero, and certainly less than 20 mg/l. If you can't answer all these demands, then skip Otocinclus.> I perform 40% WC every 5 days, so I think I would be able to keep that many fish and maintain good water quality. What are your thoughts? <Best avoided, frankly.> Thank you, Evan <Cheers, Neale.>

Re: Question for Neale about TFH article plus Corydoras  1/14/08 Dr. Neale, <Evan,> Thank you for your responses to my questions about Otocinclus. Through my web-based research I thought that supplementing the Otos' diet with Nori and vegetables would be adequate, so I'm very grateful for your input on the matter. <You may be fine doing precisely that, but the cold, hard reality of the matter is that whatever people do, most Otocinclus don't seem to survive long in anything other than a big, mature tank with plenty of algae. Their diet is a subject of some discussion among hobbyists. They may be partly parasitic as well as algae-eaters: in aquaria they have been reported MANY times to eat the mucous and skin from large, slow fish. I have seen this myself, my Otocinclus causing a significant amount of damage to the body of an Awaous goby. Do they eat mucous only when hungry? Is it something they do regardless? No-one really knows.> On the subject of the Corydoras hastatus & C. pygmaeus: I currently have medium to large "aquarium gravel" (colored pebbles) up to about 1cm in diameter. Would this substrate be acceptable for keeping either of the above Corydoras species? <Acceptable yes, ideal no. With all Corydoras, the best results come with lime-free sand, simply because it's more fun to watch them plough through the stuff. That said, the midwater Corydoras species like Corydoras hastatus likely don't care either way.> If not, what kind of substrate do you recommend? <The best for a small, planted tank is unquestionably black sand. Looks lovely, and because it removes upwelling light, fish adopt their brightest colouration.> If I need to replace the gravel, what is the best method? <If you have an undergravel filter in your tank, best not to change the gravel at all. But if the gravel is purely decorative, there's no real problems. Just take all the fish out, put them in a tub or bucket with the filter connected to that vessel so the bacteria stay happy. Then empty out the aquarium, remove some or all of the gravel, and then add the cleaned sand to a depth adequate for the plants. If no plants (or at least no plants with roots, as opposed to epiphytes) then you only need 2 cm/1 inch of sand.> Again, thank you for your help. Evan <Happy to help, Neale.>

Otocinclus with bloodworm stuck in mouth -- 1/2/08 Hello, <Lydia> We are pretty new at this. One of our Otos has a bloodworm in his mouth which he appears to be trying to spit out without success. It keeps popping partially out of his mouth, but he does not or is not able to completely eject it. Nor has he swallowed it. This is the first time I have ever seen an oto with a bloodworm, although doing a search it appears they sometimes eat them. Is he likely to eventually swallow it or should we attempt to extract it? <Leave it as is... more potential harm in trying to remove> I really fear doing more harm than good. <Agreed> Other than what looks like attempts at spitting out the worm he is acting fairly normal still. It is not always hanging out - it disappears in his mouth and then he seems to try to spit again and part of it comes out for a little before disappearing again. It has been about an hour or a bit more. We appreciate any suggestions on whether we should try to gently catch him and pull it out (although I am not even sure we could get hold of the worm) or leave him alone. I tried calling the local fish store, but they are closed for the holiday. Thank you! - Lydia <Many fishes have "rear pointed" folds, other mechanisms to direct foods/prey downward into the gullet... once swallowed to some extent... only one way to go... I would feed your fish/es more fine/chopped foods. Bob Fenner>

Re: All is well - was Otocinclus with bloodworm stuck in mouth -- 1/2/08 Hello again, <Howdy> We successfully extracted it, which went surprisingly easily. He is back in his home and hopefully none the worse for the wear. Thank you! Lydia <Thank you for this follow-up. BobF>

Oto Quarantine Question (RMF please comment/correct)   12/29/07 Hi Crew! Happy Holidays to you! <Thanks!> I have some Otocinclus and Corys in quarantine. I got them the day before yesterday and all have been acclimated into the quarantine tank and seem to be doing fine. I have some driftwood in the quarantine tank with them. <Good. Also remember they need MASSES of oxygen, and will often suffocate under less than perfect aquarium conditions. These are fish of very shallow, fast-moving streams.> I have lightly fed frozen bloodworms (the Corys ate them, I didn't see the Otos eat these) and Ocean Nutrition Formula One flakes (I saw one of the Otos nibble on these). Today I am going to blanch some zucchini for the Otos. <Hmm... Otocinclus are really pretty much green aufwuchs/algae eaters in the wild, taking in the algae and the tiny animals hidden among it. In captivity they can be tricky to feed without healthy growths of green algae. Do try prepared alternatives such as crushed tinned peas, Sushi Nori, algae wafers, etc. But the best is nice lumps of green algae grabbed out of a clean pond. The lifespan of Otocinclus in tanks with no/little green algae is very poor. Brown algae, blue-green algae, red algae (hair algae), etc. are not substitutes! It has to be GREEN algae, the fuzzy leaf-green stuff that grows in clean, brightly illuminated tanks.> I've been reading WetWebMedia (love your site!) and saw that Otos can be a host to a number of parasites. While in quarantine, should I give them medicated food for parasites and or Treat with Fluke-Tabs for parasitic worms? If so, what type of food? I'm not really sure if the Otos will eat it. <Your main problem is diet: in my opinion the majority of Otocinclus starve to death, and if parasites are an issue, it's mostly after they've been starved into a state of weakness. So your quarantining is as much about fattening them up as fixing any parasites. In any case, getting these fish to eat medicated food will be tricky, so the simpler option will be to add something to the water, such as Fluke Tabs. That said, Otocinclus are peculiarly sensitive to chemicals in the water, and I'd tend to treat them only if there were signs of ill-health, or at least no signs they were fattening up. RMF may disagree/have alternative thoughts.><<I do not. Commercial importers might do this... to benefit, but most imported members of the genus are so "beat", starved, that it's best to not quarantine them at all... but introduce directly to the main/display and get feeding ASAP. RMF>> If I should treat the Otos, should I do while the Corys are in the tank, or after they have been moved into the main tank? <I'd do them together, if required.> Thanks for your answer, and for this wonderful site! Happy New Year. Michelle <Cheers, Neale.>

Otocinclus With Parasites -- 10/09/07 Hello crew, My Otocinclus looks very sick. A light yellowish lump in his mouth appeared yesterday, now there's more lumps; and his breathing is a bit slower. Otherwise he's acting pretty normal, still active and trying to eat up algae; his color also looks fine except for 2-3 white dots that are possibly ick. I've attached a picture of his sucker mouth. I had water condition problems a couple months ago, my tank was about 1 month old then. It's now about 3 months old; I was able to keep water conditions good since I had the previous problems: which were high ammonia, pH dropped. Unfortunately though, two days ago, I did a 25% water change, and probably scrubbed the pump/filter assembly a little too fervently, so the ammonia went up slightly; probably got rid of too much good bacteria? I used some ammo lock to decrease the toxicity level, and have been doing partial water changes daily to stabilize the ammonia level. I only have two fish in the tank currently, and the other fish looks fine so far. I looked on your site, and some fish disease information online, but I can't seem to figure out what the lumps are. Any tips what I should do? Thanks so much for all your help; you guys had great advice for me the times I've written so far!-Vanessa < These little sucker mouth catfish come from warm soft acidic waters of the Amazon basin. They are wild caught and can be a host to a number of parasites. Treat with Fluke-Tabs for parasitic worms and try to maintain good water quality to prevent further stress on your fish.-Chuck>

Unidentified Otocinclus illness 7/6/07 Hello all, I am new to posting on WWM, but I have found your site to be very informative. It has helped me better understand my tank and helped me prevent more than a few problems from happening. <Am very glad for this aiding> I have a 29 gallon freshwater, planted tank that is just under 6 months old. The tank has been cycled for approximately 3 months with ammonia and nitrite steadily at zero. The nitrate vacillates between 5 and 10 ppm. My pH is about 7.5 (I use tap water which has a pH of about 8.2 and I use a Neutral buffer, but 7.5 is as low as it goes; I also use driftwood in the water, but my pH is still around 7.5).I do 25% water changes on a weekly basis. The tank has both fish and shrimp. There are 5 zebra Danios, 4 dwarf neon rainbowfish (2 male, 2 female), one young Bushynose Pleco, a 2" SAE (which I am working on removing from the tank), <Are not easy to catch!> a pair of orange platies, a pair of honey dwarf Gouramis, 1 bumble bee goby, <Mmm, actually more of a brackish organism> 2 Otos that are gray/black and 1 Oto (labeled by the LFS as an "Oto niger") that is brown. In terms of shrimp, I have 5 red shrimp, 4 Amanos, and 1 green shrimp (that has changed color to a deep red). I do not have a CO2 set up (much to the dismay of many of my fellow planted tank enthusiasts). <Mmm, okay> I have had the Otos for nearly 5 months and one died unexpectedly (that is no sign of illness, discoloration, strange behavior) about three weeks ago. This happened to be the day after I introduced the Oto niger. <Mmmm> I was shocked since the Otos are always so active. However, now I have noticed that one of my gray/black Otos has some discoloration. The only way I can describe it is that it looks like it is wearing a yarmulke/skull cap. <I see this> It is a clearish sort of circle on the top of its head. I have attached a photo for you to review. The fish seems much more lethargic than usual (and than its fellow Otos) and I am not sure what sort of illness it is or if/how I can save this fish. I posted something on my planted aquarium web group and one woman said she had the same problem, but no idea why or how to deal with it. Her Oto just died from whatever this is. I am hoping I won't have to lose another fish. I look forward to your reply. Any advice you could offer would be great. Brian (in SF) <This marking appears at times from animals that have been damaged in shipping (their heads rubbed repeatedly by others in the bag)... and by negative interaction with other Loricariids... I would keep a sharp eye out to see if the Bushynose of congeneric (other Otocinclus species) is working this fish woe. No "treatment" other than separation is recommended. Bob Fenner>

Re: Unidentified Otocinclus illness (follow-up)   7/7/07 Hey Bob (and others), <<You've got one of the 'others' this trip, Brian. Tom with you this time.>> Wow! Thanks for the reply! You hit the nail right on the head with the other Loricariids. <<Bob's pretty good at hitting the nail on the head, Brian.>> About three hours after I posted this, my Bushynose Pleco was trying to devour the Oto. The Oto was actually still alive and I managed to startle the Bushynose Pleco off. The Oto swam away. However, the Oto was clearly wounded because about 10 minutes later one of my Amanos had the poor fish by its tail and was trying to drag it around the tank. I tried isolating the Oto, but it appeared to be dead - no movement, discoloration, etc. Of course, I went to dispose of it in the toilet and it started to move again. However, I figured once I had exposed it to the untreated water (chloramine) of the toilet there was no coming back. <<A bad day all around for that poor, little guy.>> Is the only way to prevent this from happening again (my other two Otos are colored just fine) to make sure that I choose an Oto with deep color to begin with? <<Not necessarily, Brian. Otos are often transported in groups of mixed species. In fact, what might be marketed as an 'Otocinclus' could very well be one of the 'Parotocinclus' species, some of which are more of a light brown (to keep it simple) in color. The so-called Golden Oto is one of these. As a small bit of trivia, a true Otocinclus does not have an adipose fin -- a small fin along the back between the dorsal and caudal (tail) fins. An adipose fin on an 'Oto' marks it as a Paraotocinclus. (If you're intent on boring someone to tears, share this with them. :) )>> The LFS from which I bought the Otos described them as high-risk fish (always!) due to the cyanide that is often used to catch them in the wild and the stress of transport. However, I figured after 3-4 months of living in a tank with good water quality that I was home free. I guess I was wrong. <<Cyanide harvesting is a valid cause but transport stress is probably more likely the culprit in the early deaths of these fish. Otos (to keep it 'generic') can't digest algae (cellulose). Rather they have anaerobic bacteria in their guts that do the work and the fish is 'nourished' off of the by-products of this process. During transport, so much of the bacteria may die off from lack of food that, even when the Oto is placed back into an algae-rich environment, the fish literally starves to death, i.e. the algae passes through the fish's system untouched, so to speak. Now, the biology lesson notwithstanding, one of the best methods of selecting a healthy Oto is to find a 'fat' one and only select specimens that have spent at least a couple of weeks at the LFS. If the fish's stomach is flat or concave, pass it by. The prospects for a skinny Oto's long-term survival are not good at all.>> Two clarifications to Bob's "mmms". I brought up the lack of CO2 setup, but neglected to say that I regularly use Flourish Excel (liquid CO2). <<Not 'splitting hairs' here, Brian, but the Excel product isn't 'liquid CO2' though it does supplement the tank with carbon, as does CO2, but rather from organic matter. (Guess that did sound like I was splitting hairs, didn't it? :) )>> Second, regarding the bumble bee gobies as brackish water species. I had read this and had crossed them off my original stocking list for that reason. However, a LFS which only carries freshwater fish (or at least only has freshwater tanks) raved about the success they have with this particular bumble bee goby in fresh water. Despite its picky eating (which seems to be common for this fish), it seems to be getting along just fine. <<I would share the same concerns that Bob, no doubt, has with regard to this animal, Brian. An LFS's short-term success with keeping a brackish species in FW doesn't equate to long-term success for you or your pet. Very often, brackish water species start out in FW but must make the transition as they mature in order to thrive/survive. Time will tell, of course, but it's best to keep an eye out for otherwise unexplained problems should they arise.>> Again, many thanks for your wisdom and your willingness to share it. <<More than happy to help, Brian. Good luck and best regards.>> <<Tom>>

Otocinclus <maybe Danio> fry, fdg.   6/30/07 About a week ago, maybe less, I had my husband remove a few plants that weren't looking so hot from one of our aquariums. He thought something along the lines of putting them in a bucket and seeing if they would look any better (It couldn't hurt) <Ahh... a good friend grows such plants almost year-round outdoors here in San Diego... spectacular results> So they were outside in a bucket...some morning sun, nothing too harsh. Tonight he was going to put the plants back in the tank and dump the bucket... being always worried about Cyanobacteria and such I bent down and peered real good at them, and noticed a tiny movement. We have some incredibly tiny fry. I have never seen any fry this small... the only breeding fish I have are angels and guppies I guess. But the tank these plants came from had: angels, serpae tetras, Columbian tetras, neon tetras, zebra Danios, Otocinclus cats and a pair of Cory cats. <I see...> After looking at someone's video of fry, it looks like they may be Oto fry... very very tiny, almost invisible from the side. So they are in the hospital tank now, along with the plants from the bucket and in the water that was in the bucket... we had heavy rains today and the bucket overflowed. We have about 20 fry left. What should I try to feed them. <"Infusoria" would be ideal... see the Net re... But a pre-made commercial food prep. is the only thing practical here. See the Net, your LFS re such... "tube food"...> I thought of rotifers since they are tinier than baby brine shrimp, but if they are Otos it would seem that wouldn't work at all. I also have a package of Hikari first bites that is as fine as talcum powder and contains many things, among them Spirulina, milt meal, along with some krill meal and such. <The liquid "tube food"... egg-yolk based...> I'd hate to see them die, especially after the miracle of even seeing them to begin with. Any ideas? If I put a hulled pea in there would they nibble on that? The plants have a little algae on them as well but the fry are so darned tiny... Julie <Might be the Danios otherwise... Oh, and congrats! Bob Fenner>

Oto <what? Oto parts?>- 6/1/07 Hi Robert, after days of hunting for Oto's I feel that it can not hurt to send you a mail. <Hello, Neale here.> > I am in Shanghai and now have a discus aquarium. In Europe I have always had Oto's in my tanks and have always been  fascinated by their behaviour and rewarded by their gentleness. Clean  plants no algae growth on the leaves etc. <Yes, they can be excellent algae eaters. But I hesitate to recommend them too widely for a variety of reasons, not least of all the fact they seem to travel poorly and the mortality immediately after import is very high.> > Plenty of algae (green) on the back wall of the tank but not a problem. <Your observation of their liking for green algae is spot-on. Otocinclus are ideal for planted aquaria where the background level of algae is low and limited to green algae types. In "unbalanced" aquaria with few/no plants, Otocinclus have no useful impact and in fact often starve to death because they will not eat the brown, hair, and blue-green algae common in such tanks.> > I have hunted everywhere to try and purchase these fellows here in China > but have had no success. <Given you are keeping discus, I would *never* keep Otocinclus with them. I have observed Otocinclus sucking the slime from large, slow fish in my aquaria, and assume that discus would be an obvious target. Other aquarists have observed this, with Otocinclus attacking angels and discus. Far better to choose something a bit large, like one of the "clown" Panaque species (such as Panaque maccus) or even Ancistrus spp.> > I am hoping that with your knowledge of these fish and your reference to the tiger Oto that has been bred in Asia that you may be able to point me in the right direction to obtain them. I have always had the Otocinclus affini but any > Oto's would be fine. <I personally don't know who is importing/trading that variety, but I'm sure if Bob does know, he'll follow up. As a general rule, placing a "special order" with retailers is often the way to go. I've done this many times.> > I apologise if this mail is out of context as I have no idea how busy you > are or how much mail you get from your site. > kindest regards > john Ramsey <Good luck, Neale>

What do I do with extra Otocinclus?  5/30/07 I have a 5 gal. Eclipse Corner Tank on my desk at work. There were 2 Betta's (with a divider) in it, but when I added 3 Oto's from PetSmart soon after the Betta's died of tail/fin rot. I moved them to separate bowls, and treated them but they died. I figured it was the addition of the Oto's so I expected them to die as well. That didn't happen. They cleaned my tank of all algae, and I feared they would have nothing to eat because it seems they won't eat the algae flakes. So, I went to my buddy's Cichlid tank and traded all the ornaments (no, I don't know if this was a smart thing to do or not, but I did it anyway). It seemed, that this brought new life to the Oto's, as very soon after I spotted little white things on the front of the tank. When I realized it was fry, I shut off the filter. I counted about 12 fry stuck the glass. I turned to the internet for advice and found little. I put a baby sock rubber banded over the filter intake and turned that back on. Added an air pump for them. I fed them boiled spinach leaves. Well, a spinach leaf from a coworkers salad stuffed in a cup of hot water. They ate little holes in that overnight. I do a 50% water change weekly, and slowly suck out the leftover food every few days to keep the substrate somewhat clean. Now I keep exchanging plants with my buddy's Cichlid tank for food and they clean it overnight. There are now 4 or 5 baby's left and they are half the size of the adults and seem to be doing fine. My question is, what can I do with these extra Oto's? Can they go in the Cichlid tank? Isn't that too much hardness for a Cichlid? Or can I support 7 to 8 Oto's in a 5 gal tank? PetSmart told me that they stock the same sex in the same tank and sell them that way so this wouldn't happen. Well they screwed up and now I have these new guy's. What do people do with their new fish when they didn't mean or even know they would spawn? <Wow. This is quite an amazing tale! On the one hand, a 5 gallon tank is really too small for Otocinclus. As a group, Otocinclus are considered "delicate" because they need good water quality and lots of oxygen. In most community tanks, they tend to be short lived. But yours are doing well, so well done! Anyway, as to where to put the Otocinclus. I personally wouldn't mix them with anything other than, perhaps, South American or West African dwarf cichlids. The problems are multiple. Firstly, yes, they will not do well in Lake Malawi/Lake Tanganyika type aquaria. Such hard and alkaline water conditions will not suit them at all. Secondly, when kept with slow moving things like angelfish and discus they tend to suck the sides of the bigger fish, scraping off the mucous. I've seen this in my own tanks, with the Otocinclus rasping away on large gobies, creating nasty blisters. Aggressive fish like convict cichlids will simply hammer them to death. So ideally, give them to someone with a peaceful community of other small fish such as barbs and tetras. PetSmart cannot possibly sex Otocinclus so their advice there was nonsense. In fact, breeding Otocinclus is quite uncommon, so you've actually done rather well.> Tom <Cheers, Neale>

Bloated Oto  3/23/07 Hi Guys: <Patrick> I have an Otocinclus that is bloated. He has a bulging belly as you can see in the pictures that are attached. Problem is he is not eating the algae from the tank. Has not been eating for quite a while (a couple of weeks) We thought he was eating excess fish food so we have cut that back and he is still as large, maybe getting larger but not eating the algae. Could he have a blockage? <Yes> We had a clown Pleco that ended up doing this too, getting bigger but not eating algae till we found him dead. <Mmm, what sorts of food/s are you feeding?> Do you suspect constipation?  I tried peas but he hasn't eaten them at all.   Bacterial infection?   <Possibly> What do I use.  One guy suggested Epsom salts, <I do too... safe, often effective... readily available> what levels in what amount of water.   <Posted: http://www.wetwebmedia.com/FWSubWebIndex/saltusefaqs.htm> I can move him to an alternative tank to set up a hospital tank. thanks for your help P. Carty <This fish may also be developing eggs... perhaps be egg-bound... I would try the Epsom per WWM. Bob Fenner>
Re: bloated Oto   03/23/07 As per the web page I will put an additional 1/2 teaspoon of Epsom salts to my 10 gal tank (I added 1/2 teaspoon yesterday).  Some additional information that may or may not bear on this issue.  I bought test kits yesterday and did testing of Nitrates and KH hardness.  Nitrates are at 80ppm and hardness at 10. <Yeeikes, both high...>   I have started 15% daily water changes with Reverse Osmosis water.  My goal is to reduce nitrates to 20 or lower and hardness to 7 (as per pamphlet that says tetras like it around 7. <Ah, good> Would these two high values have any bearing on the bloating of the Oto? <Oh yes... of a certainty> You had asked what kind of food I was feeding them when I mentioned our late Clown Pleco.  We are feeding TetraMin tropical flakes. <Mmm, I would augment this with either some other prepared food/s or give them a "treat" of some frozen/defrosted meaty foods at least once a week> Thanks again for your advice. <Welcome! Bob Fenner>

WetWebMedia Website Otocinclus Article You Wrote, AFM acronym meaning  Hello,        I came across an article you have on the web regarding the species of catfish known as Otocinclus.  At the bottom you have a bibliography.  In it is a line that says Castro, Alfred D. 1996. Algae al fresco: Exactly which algae eater really likes to chomp down on this stuff? AFM 12/96.  What does AFM stand for? <Sorry for this: Aquarium Fish Magazine... Bowtie Press nowadays... a pulp 'zine out of... California. Bob Fenner> I want to read what you read.  It is on http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm. Thanks, Jonathan

Question Re: Oto placement   12/10/06 Hi Tom, <<Hey, Sean.>> I have another question for you already. <<Let's hear it...>> I was at a major chain pet store today, and much to my surprise, they were selling Otos (Otocinclus) for $1.99. Since this is the first time I've seen them in my area, and that price is too good to pass up, I bought 3 (I read on WWM that they do well in groups). I have 2 tanks, and I can't decide which one they would do best in. <<The quarantine tank, Sean. (Being a little silly but I'll explain.) The store I buy my fish from, my Otos included, is, literally, a 'Mom and Pop' operation and won't sell their freshwater animals for the first two weeks after they take delivery, i.e. they quarantine them all. Saltwater fish are held for four weeks with cards posted on the tanks showing the dates that the fish arrived at the store. That said, I can guarantee that this isn't the case with your Otos. Point number one. Next, Otos are notorious for being difficult to acclimate. Wonderful little guys that they are, they're easily lost early on no doubt due to the stress of transporting, handling, lack of sufficient food and -- the big one -- means of capture. Because of their tiny size and naturally tangled environment, many (most?) of the Otos that reach the store have been taken in the wild using cyanide, or other chemicals, to disable them for collection. (I would be skeptical that 'tank-raised' Otos would be going for $1.99 each. Mine were $3.99 each which I thought was a bargain.) The upshot here is that these chemicals can remain in the internal organs of the fish either shortening their natural lifespans of about five years or leading to a much, much earlier demise. Darned hard on the Oto, to be sure, but if one is lost and picked at by another fish, it, too, may end up with contamination from the chemicals I referred to. Now, let's move on to your options.>> Tank one is a 24g tall/show tank, moderately planted, with a cheap "fizz tab" CO2 system. Its inhabitants are 4 Opaline Gouramis, Trichogaster trichopterus (2 are the gold variety), 2 paradise fish, Macropodus opercularis, 2 Ramshorn snails, and one common Pleco, who will be re-homed soon as this tank will be way too small for him (he's only about 4" right now). <<Sounds like a good choice, Sean. And, I appreciate your thinking regarding the upgrade for the Pleco.>> Tank 2 is a 5g, moderately planted, with no CO2. Its inhabitants are 1 Betta and 3 cherry shrimp. <<Could be a good option as well but, personally, I like to add some aquarium salt in with my Betta. Your Otos would 'tolerate' the amount of salt I use but I don't think they'd appreciate it very much.>> Both tanks have laterite and gravel substrate, a good amount of driftwood, and a pH just above 7. Neither tank has much of an algae problem, although both tanks have small amounts of green "spot" algae. Now, here's my question: which of these tanks would be a better fit for my Otos? <<As you may have gathered, Sean, I like the larger tank for your new pets. The smaller tank would likely work just fine but I'm not a huge fan of keeping Bettas with other fish. Just me, perhaps. Also, if you do decide to add salt to your Betta's tank down the road, and I do recommend this, it probably wouldn't sit well with the Otos if they were in the tank.>> Sean <<Enjoy your new fish, Sean. Tom>>

Once playful Otos are now lethargic   7/28/06 Hello there, <Hi from... HI!> For the past 5 months, I have owned a 46 gallon, unplanted tank, containing 10 rummy nosed tetras, 10 black phantom tetras, 4 peppered Corys, and 3 Otos. <Better with live plants...> The Otos were originally quite playful, moved around the tank, stayed within view, interacted with other fish and ate any algae that appeared.  However, for about the past month, the Otos have been in hiding. <Something in the way of water quality changed> Now I hardly ever see them, and algae is building up on the glass and plastic plants.   They don't appear to be sick, and none have died.  All the other fish appear to be normal.  My water temperature has increased to about 82 degrees due to the warmer summer weather, but besides that, I can't think of anything that I've changed. I do 20% water changes once every week or two, and nitrate level is 12.5 mg/L or lower (my test kit measures only measures 1, 0, 12.5, and 25 mg/L).  I don't add any "Oto specific" food to the tank.  Might I simply have more algae than they can handle, allowing them to become more "lazy"?  Do you have any thoughts on the matter? <Yes... I definitely would add some live plant material here... Will address many possible ills, shortfalls that could be at play here... Dissolved oxygen, food, shelter...> Thanks in advance for your help. Bonnie <Welcome. Please read here: http://wetwebmedia.com/FWSubWebIndex/otocinclusart.htm and the linked files above. Bob Fenner> Otocinclus and Comet DON'T MIX! EMERGENCY  07/21/06 Hi, love your website, thanks for it, but I have a huge  problem!! <<Hi, back. You're welcome. Let's see what we can do. (Tom here, by the way.)>> I woke up today to find my Comet munching on my Otocinclus! Actually, what I mean by that is that the Oto was lodged in his mouth with about 25% of it sticking out. He doesn't appear to be choking because he is still breathing. <<I assume you're referring to the Comet because the Oto doesn't sound to be in good shape.>> I got two new Oto's a couple days ago and since then they've both been lethargic with clamped fins, each was tiny, 1 inched guys and my Comet (Harry, don't ask) is about 4 inches long excluding his tail. He's always been greedy and   I think what happened is the Oto died and the Comet finally could catch him and did. <<Not unusual for Goldfish to do this. They tend to be "opportunistic" feeders and your Oto gave Harry the chance he was waiting for...unfortunately.>> No search engines helped me at all! <<In fairness, it's not the typical inquiry.>> At this point, Harry is moving slowly and keeps sucking or blowing his mouth, I can't tell which. This is a major problem and one way or another might solve itself before you answer back, but right now my main concern is lack of ability to eat or transfer air in the swim bladder, and of course lodging it in more and choking! <<As long as he's moving water over his gills, he's not "choking". He may not be very comfortable but he won't suffocate.>> Just in case he lives and for future references please help! I tried using metal tongs and I grabbed the protruding tail but I couldn't get it out, I'm sort of nervous of pulling too hard. How do I dislodge it, or can he digest the head soon enough and eventually pass it through?? (I seriously doubt it though.) <<I seriously doubt it, too. Goldfish are primarily "vegetarians". Their systems aren't developed for dining on other fish. Likely the dorsal rays are getting caught in Harry's mouth as you try to pull the demised Oto out. You might try twisting the Oto one way, or another, to get the rays to "release".>> And should I remove my other Otocinclus and my (very lively and quick) Algae eater? <<First, if by "Algae Eater", you're referring to a common Plecostomus, I wouldn't worry about this. Harry isn't likely to be interested in a "lively and quick" tankmate. My concern here, without getting on a soapbox, is that many Otos are "captured" in the wild by the use of cyanide. I have no direct knowledge of these fish being bred in farms, though it's entirely possible that they are. In any event, the fact that both of yours showed signs of lethargy and clamped fins indicates, to me, that it's possible that they were taken with cyanide, a chemical that will, unfortunately, stay in their systems. Otos, regretfully, show an inordinate amount of "infant mortality", meaning that they often die within hours, or days, of being introduced into the tank. Fish that feed on the dead fish are going to be ingesting cyanide if the deceased fish contain this in their bodies. My recommendation is to get the Oto out of Harry's mouth regardless of what it takes and remove the other Oto from the tank. Easier said than done, I know, but you must do this.>> Thank you for your time, and sorry my email is so long. This is my first major goldfish problem and I'm very anxious. <<Not to worry. You're more than welcome and I completely understand. Tom>>

Breeding Otocinclus ... Neat!   6/22/06 Greetings, and thank you for your site, it has a wealth of information. I was particularly excited to see a letter from Andrea Hall entitled "Tiny White Bugs in a FW Set Up  - 03/25/2006" in the "FAQs on Otocinclus".   I don't have a question for you, but rather I'd like to make a comment about that letter and relate an experience of my own. Andrea expressed concern over some little white specks she had discovered in her tank when examining her Otocinclus which "was more than just plump, it was huge" and had submitted photo's of her Oto and the specks.   One reply from Chuck suggested they were probably a form of daphnia, RMF suggested that they indeed were likely to have been fry.   I had an experience with my two Otocinclus this past weekend which would confirm that they are indeed fry. This past Saturday my wife mentioned to me that she had noticed the previous evening that the Oto's appeared to be spawning, I took a look and found that it seemed they were, the female's belly was extremely distended - probably two to three times its normal size. The male who normally paid little to no attention to her was frantically following her around the aquarium. As she seemed to stop and clean a spot of glass or a plant leaf he would cling to her or next to her, sometimes wrapping his body around the top of her head so the two of them formed a "T" shape, and sometimes clinging to her back or side.   Searching the internet I found precious little in regards to Otocinclus spawning, but I did find that the behaviour was supposed to be a fairly common mating routine among their relatives. So I assumed that they were breeding. The behaviour continued for many hours.   The following day the females belly was back to her normal size and the two were back to their normal routine - eating, resting, and pretty much ignoring each other. I tried to find eggs in the tank but was unable to see anything. While looking for eggs though, I found the same little white specks throughout the tank as Andrea described, they were everywhere, numbering easily in to the hundreds. And, as Andrea described, they moved much the same as the full-grown Oto's.  I too, thought they may be some kind of invader in my tank, but found the coincidence of their arrival and my Oto's deciding to spawn just a bit too convenient. So assumed they were fry. Then today I ran across Andrea's photo's on your FAQ page.  My fry look exactly like her white specs.   I'm just as shocked as I am excited, this is a small five gallon tank that I keep slightly brackish for the sake of the green spotted puffer who was it's sole occupant until putting the two Otocinclus in to eat the algae about three or four months ago. I felt bad about putting them in that tank, feeling the salt content may be to high for them, but they have thrived and by this recent sequence of events I'd judge them to be quite content in their home. Incidentally, the salt content is about 1 teaspoon per gallon, half of which is aquarium salt and half marine salt.  I am sending you links to video I took of the spawning and of the fry. They are quite large videos not too suited for dial up connections, and even on high speed will take about a minute to load. If you'd like links to video more suited to dial up let me know and I will make them available.  Link to breeding video : http://www.farrant.info/video/Otocinclus_breeding.wmv Link to video of fry : http://www.farrant.info/video/Baby_Otocinclus.wmv I'd be very interested in any comments anyone may have, and very grateful to any tips anyone may have to help me raise the fry successfully. I have rounded up any plants and algae laden materials I could find from my other tanks to help supply them with food as well as making a broccoli paste for them. The puffer is getting moved to a different tank, I have turned off the filter so their pinpoint bodies don't get sucked in - to help compensate I have increased the airflow in the tanks bubbler and am doing daily trickle water changes with aged water.  Thank you, Bill Farrant < One of the great things about the internet and this website is the information that gets passed around. Oto's are very cheap algae eaters than many breeders have no interest in breeding because there is no money in breeding them. That is why you have had trouble finding any info. In the previous letter you referred to, I was unable to bring up the photo and wrongly assumed they were daphnia. Bob was able to get the photo up and posted on the website. I looked back and saw the photo and knew that they were fry. This information is very useful because there are many other Oto species that are very attractive but very expensive too. Breeders may be willing to obtain these new species if they knew how to breed them. Thank you very much for sharing this info.-Chuck>

Tiny White Bugs in a FW Set Up  - 03/25/2006 Hi.  I have a question that I haven't been able to find an answer to.  I have a one gallon tank that I keep on my desk that has a Betta and 2 Otos.  I've had the Otos for about 6 months.  I put some shells in the tank a couple of months ago and the two Otos have been hanging out under one of them a lot.  I noticed a week or so ago that one of them looked a little plump, but I had been told it was very unlikely they would ever reproduce (I didn't really want them to).  Last night, I noticed that the plump one was more than just plump, it was huge.  I then noticed dozens of little white specs moving about the tank along the bottom and the sides.  I was worried that I had some kind of infestation, but the specs moved in the same way as the adult Otos-- very jerky, swimming to the top occasionally-- so I assumed they must be fry.  I removed the Betta.  I noticed a little while later that the larger Oto was floating, dead.  It looked like it had blood in its abdomen. My question has to do with the little white things.  Are Oto fry really THAT tiny?  Or is something else growing in my tank?  I searched the internet for answers but it doesn't seem like many people have much luck breeding them.  I scooped up a few and took them to the pet store, but they were so tiny no one could tell me for sure what they were. < Your Oto's died from an internal bacterial infection. The tiny white bugs are probably a form of daphnia that came in with the sand or even a plant. It can be treated with Fluke-Tabs.-Chuck> If you don't have an answer either, that's ok.  I'm going to have to break down the tank when I move out in May, so whatever they are, they probably won't survive the move.  I've attached a couple of photos I took. Thanks Andrea Hall <<To RMF these do appear as fish fry... I would not be so sure that these fish did not reproduce. RMF>>


Otocinclus question ... plants/comp.    3/18/06 I have several Otocinclus catfishes in a 46 gallon freshwater tank with 2 Gouramis, a couple of tiger barbs and 2 clown loaches.  Just last weekend I purchased several nice Amazon plants and to my dismay they seem to be getting little holes in the leaves, about the size of the Otocinclus' mouths! <Ah, yes>   Could they be the culprits, I haven't seen any other of the fish hanging around the plants? <Could be... but also the barbs, loaches... however the Otos are most likely at play here> I found reference to them needing plants around but I wasn't sure if that was for hiding places or to eat. <Mmm, both and more. Bob Fenner> Thanks, Olivia

Getting food to the Corys and the Oto   2/22/06 Hello WWM crew, I have searched your site and I think the single tiny wiggly white worm I just saw in my tank is Planaria.  It is a very very fine threadlike white worm of about 5mm length. I probably only saw it because I was sitting very close to the tank. Am I right in understanding these are from too much waste product and uneaten food? <Yes.> Do you have any delivery tips for the food?  I was afraid if I hid it the Oto and Corys would not find it either. I have a bit of driftwood with a plant on it that I can put food under but it seems nearly all the fish can wiggle in there to get it! I thought my tank was very very clean.  I change 25-30% of the water once a week with another bucketful or two changed halfway through the week as I don't like to see the Corys searching around for food in droppings. Yuk. I vacuum the open area of gravel once a week and stir up the other areas with the siphon hose as the vacuum wont fit amongst the plants.  I have quite a lot of live plants. My problem I guess is I have been overfeeding although everything gets eaten quickly. <I agree.  Your vacuuming technique sound very thorough.> I am always worried about getting enough to the Corys and the Otocinclus.  The other fish are total pigs and tend to eat everything. I feed a couple of pinches of flakes <Try backing off a bit.  Try to lure those speedy Tetras away by sprinkling a bit on one side of the tank, and then sprinkling the rest far away from them.> , two sinking Cory-food pellets <Feed just one pellet.  Break it up into a couple pieces, always drop it in the same place in the tank every day, so the Corys get into a pattern/know where to find it.  Feed the Corys about 1/2 an hour after you turn off the light tank light.>   and a half of an algae wafer once a day with a day of no food now and then. <Leave the wafer as a treat for every now and then.> Also feed a frozen bloodworm cube once a week and some cucumber every few days (the Oto loves that). <OK as long as you are subbing this for the other foods you described.> I have a 26 gallon freshwater tropical tank (AquaOne 620) with a filter and lights built into the hood Temperature about 78 degrees. Ammonia and Nitrites are zero. Tank has been set up for 10 weeks and is fully cycled. The tank is stocked with: I angelfish 3 black skirt tetras 5 Corydoras 2 dwarf Gouramis 1 Otocinclus <A bit heavily stocked for that size.  Probably contributing to the waste/food levels for Planaria and algae.  Your Angel will get quite large, produce even more waste.> I tried leaving the lights on a bit longer to grow some algae for the Oto...but instead of the brown algae I once had green algae has grown on some of the Anubias and Oto doesn't seem to make much difference. So that might have been a mistake? Do you think if I revert to my original 8 hours of light the Oto will eventually eat it all? <Go back to 8 hours.> Or maybe should I get an additional Oto? <Otos do prefer the company of their own kind, but you are already heavily stocked.> So much to learn.  Any advice you can give would be very much appreciated. Many thanks, Gillian  : ) <Jason N.> PS I think your site is terrific, you folk obviously love what you do although I expect if you get many more "My Betta sits at the bottom of his bowl" questions you might implode. <Thank you!>

Re: Getting food to the Corys and the Oto   2/22/06 Thank you Jason for your speedy response, I was very disappointed when I did my own sums and realized "no more fish for me"....well, in this tank anyway.  Everyone laughs when I talk about my next tank. <You've been bitten by the bug.  God have mercy on your pocketbook.> This one is a practice to see if I can keep up the enthusiasm before going mental on a giant tank. <I find that my largest tanks are the easiest to care for.  It is far harder to make most mistakes in 50+ gallons of water.> You know what?  I think I can! <Glad to hear it!  Now there is only the problem of what you're going to do with your current tank when you get a new one...> Thanks again from Australia, Gillian  : ) <Jason N.>

Query pregnant Oto  11/16/05 Hello, I read your article online and was hoping you can help me.  Up until I read your article today, I had only read that Otos did not breed in captivity. <Rare, but has happened> I was quite concerned, therefore, when I saw one of my Otos looking "very" pregnant...or deathly ill.  I have a planted 60 gal tank, 2 fancy goldfish, 5 Otos and too many fancy guppies. The tank is around 24*C, 2 large driftwood, lots of plants including a huge lily with leaves averaging 6+ inches diameter. <Neat!> Water parameters very good. None of my fish have died or been ill for over 2 years. All five Otos were purchased approximately 14 months ago. I have a grave concern that either my Otos is horribly diseased with something... or pregnant. I don't know which so I am hoping if I describe her to you, you may be able to tell. <Okay> The other 4 Otos have not altered in either appearance or behaviour. Lately one or two of these "healthy" Otos are literally side by side or nose to nose with the Oto I am concerned for. <Are social animals, but...> While the Otos often roam/sit together (within a few inches to 1 foot) I've never really noticed this closeness to this degree. I am concerned they know something is wrong with her or, best case scenario, they are a mated pair. Sick/pregnant Oto appearance: Normal sized round/plump whitish tummy now hugely distended. Looks like a round small marble of approximately 3/8's of an inch in diameter. Tummy definitely round, neither oval nor flattish. Red streaks appear in the formally white area of her underside and tummy, including near face/jaw/mouth. <The reddening may be trouble> Sick/pregnant Oto behaviour change:  * Once saw her hanging onto driftwood (vertically and right side up) with just her mouth and tummy about 1/8 inch from driftwood  * Sits "on top of" a particularly flat sitting (underwater) lily leaf. The leaf is about 6-8 inches in diameter but she seems more interested in just sitting/sleeping there than eating on it. While she's there one other Oto seems always there as well. * While the Otos go everywhere in the tank, the length of time she spends just sitting there is unusually long and the fact that the other Oto is there is very unusual. * The red streaks scare me and even her eyes look reddish and/or distended?? <Not good... not normal reproductive change> Sick/pregnant Oto behaviour non-change: Still busily munches on algae and driftwood.  I would greatly appreciate your opinion, references and help. Thank you, Eileen Reid <You will soon know... the very round appearance should not persist more than a week... the female will lay her adhesive eggs, with one or male present, and they will provide some guarding behavior, not moving much, for four or so days until they hatch... Bob Fenner>

Re: Query pregnant Oto, Net Virgin  11/17/05 Hello, I read your reply. Thank you.  This is the first time I am using the internet for this so don't know how to reply/ask more questions. <This is fine> The Oto is still alive. I picked her out of the aquarium yesterday. She didn't struggle at all which surprised me. <Me too> I just gently picked her off the side of the glass. I held her in my hand an looked at her really closely.  She has clear fluid inside her tummy. It's as though clear fluid is surrounding her internal organs. Her scales do not stick out. The Red area seem more localized at the bottom part of her tummy, and I would say, out of the water, the "round marble" is actually more of a "flattened" marble. If she is not pregnant, can you think what could be wrong? <Could be Ascites from some cause, or dissolved egg mass... or?> or is there anything I can do besides waiting? <Perhaps adding a level teaspoon per five gallons of system water will help "move" whatever this is> I put her back on a leaf and she swam onto another area. I checked on her this morning, and she's still alive (and had move to another plant).  If she is ill and she dies in the aquarium, will whatever she has pass to my other Oto's and Goldfish? Thank you, Eileen <Not likely. Bob Fenner>

Re: Query pregnant Oto  11/22/05 Hello Robert, Well, she's still alive and still looking much the same, so I doubt she is pregnant. The one bad thing in addition to everything else is, it appears the linear stripe down her side is faded and is now almost non existent. On the bright side, she is still eating and none of the others have her appearance. I'd say the other Otos have changed in that the one always around her is no longer at her side. <Not pregnant... egg-laying... for this long> I am hoping she'll get better. I looked up "Ascites" on the internet, and the more I read, the more I think this is correct. I could put her in a little container to: "<Perhaps adding a level teaspoon per five gallons of system water will help "move" whatever this is>" A few questions: -what is it I should add? <Epsom Salt... aka Magnesium Sulfate> If I segregate her into a little container, will she die from shock? <Better to treat all... in place> And what about light/heat.. how much? <Would not change these> Should I give her a plant or something? <A good idea.> At this stage, do you think there's any hope of the fluid leaving on it's own? <Oh yes> Thank you for your help, Eileen <Welcome. Bob Fenner> 

Re: Query pregnant Oto - 11/25/2005 Hello Bob, <Actually, Sabrina here, in his stead; he's out of the country for now.> Thanks for your help.  Unfortunately she died last night.   <I am so sorry to hear this....> I saw her on a leaf earlier in the night, then saw her upside down (still bloated) on the bottom.  I picked her up and to my surprise, she struggled a little. I put her back on a leaf, but soon after she tumbled down again and lay upside down. I left her till very late, then thought I'd check again since she hadn't moved. She had died. <My deep sympathies to you.> Would you have any idea what caused this? <There are many possibilities, here.> Everyone in the tank still appears okay, and as I said before, I got all the Oto's over a year ago, so whatever was wrong, it had to come from me. <No, actually, this could have been something a long time coming....  no need to put blame on yourself, here.  Bloating like this often happens as a result of internal bacterial infection.  Bacteria that cause such infections are often present constantly in aquaria, and only actually become problematic when a fish has a depressed immune system.  An injury, a genetic weakness, a disease the animal has been fostering for some time (Mycobacteriosis, for one example) all can cause such a thing to happen.  It is unlikely that this was a result of anything you did or didn't do.> Once again, thanks for you quick replies and expertise. <And thank you, very much, for your correspondence.> Happy Thanksgiving! <To you and yours, as well!> Eileen Reid <Wishing you well,  -Sabrina>

Otocinclus Article 9/26/05 This was by and far the best article on Otos that I found on the Internet http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm THANK YOU!!! <Welcome, BobF> John Miullo

Firemouth Bit Off More Than He Could Chew I tried throwing some Oto's to clean up in my cichlid tank. A few days, all was well, but yesterday morning I see a tail sticking out of my Firemouth's mouth. Nothing I hadn't seen before, except that the tail end was still sticking out last night, and this morning as well. I just got home from work and he still hasn't been able to swallow it down. I thought of netting the Firemouth and trying to pull it out, but I figure that I can end up tearing up his throat. He doesn't seem overly stressed about it, and has even kept up his harassment of a larger jack Dempsey in the tank. I believe he was even eating some of the flakes I threw in earlier. Having been at least 36 hours, what should I do? Keep waiting and hope he eventually gets it down, or try and pull it out even though I may do a lot of damage? Anyone else have this kind of problem before? < Unfortunately, Oto's like most catfish have stiff spines that they use for protection from predators. I would take him out and get a good look at the mouth. I would be tempted to take a pair of small scissors and cut the spines on the Oto and extract the body. Then use tweezers to extract the spines. If you can't pull them out then I would push them through and pull them out from the other side. Not often but it happens.-Chuck> 

Dying Otocinclus - Capture and Holding may be the Culprit Hello. I have two planted 30 gallon tanks. A couple weeks ago I bought 6 Otos to put in them to help with algae, and five of them died a few days ago. I'm running CO2 at about 20 ppm, overdriving 2 18 watt bulbs, pH is 7.0, KH's are 5-7. None of the other fish died. Haven't tested nitrates lately, but in two weeks prior to buying the Otos, I did four 50% water changes (I know that's a lot, but I haven't lost any fish in doing so). Prior to that, nitrates were about 10-20 ppm, so I can't imagine they were a factor. I can think of only two possible causes: 1) I have slow release tablets for my swords; perhaps the Otos were nibbling on one of those that got shifted to the surface somehow; or  2) I added Fluorite iron mix the day before they died. They recommend 1 mm/ten gallons, I perhaps doubled that, if that much. Never had any trouble before. Do Otos have a greater sensitivity to iron that most other fish? I'd rule out stress as a factor, since I have lots of nooks and crannies, and they were eating like pigs the day before they checked out. The one remaining munches continuously. I have tiger barbs in one tank, but they, nor any other fish, acted aggressively towards the Otos. I'm puzzled, because I'm told they're so hardly, except for high nitrates. Thanks very much, Mark < You Oto's actually died from starvation and or a vitamin deficiency. Oto's are caught in the wild and held for a long time. Maybe weeks before they reach the store. They need to eat a little bit every day to stay healthy. After such a long time their long intestine becomes depleted and they start wasting away. You buy them and they start to eat like crazy. Unfortunately algae has a very low nutritional value and they need to eats lots of it for a long time to build up their strength. Most of the time it is too little too late and they die.  This happens with Pleco's too. The remaining fish then do Ok for a long time because there is lots to eat for them. Next time I would recommend that you only buy Oto's or Pleco's with full bellies. Not concave or hollowed out. Next , place them in a quarantine/hospital tank and feed live black worms algae wafers and guinea pig pellets. The worms will give them some instant digestible protein. The algae wafers will give them some binder with minerals. The GP pellets are vitamin C enriched alfalfa that supply roughage as well as protein and vitamins. Many of these fish require highly oxygenated water with a current. Many aquarists go without a strong current because they will lose their CO2.This will be very helpful for these little guys.-Chuck> 

Otocinclus with Veracity Dear Sir, I just wanted to say thank you for your article concerning the Otocinclus at http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm. Not only is it well written and easily understandable, but you also took the time to write your references, which gives the article credibility (a rare thing on the internet). I am certain my Otocinclus will benefit greatly from the time you have given to write this text. Thanks again :) Guillaume Pomerleau :) <Thank you for your kind, encouraging words. Am hoping to continue writing such in the years to come. Bob Fenner>

Cycling, timing, and Endler's Dear WWMites, <<Kewl. I'm an official Mite!!>> Well, thanks to the rest of your site (and I thought I'd read nearly everything before), I've answered my own questions.  Wow, y'all have a lot of stuff for us to read!  I backed out to the home page and found more links to more info a bit farther down.  Unfortunately, the intense absorption of so much info knocked most of the third grade out of my head to make room.  Ah, well, third grade was a bust anyway...  To recap: We'll get the Otos much later in the process rather than earlier, and our earlier decision on five (one per ten gallons) is apparently a good population.  Also, my bride and I decided we're going to replace several of the silk plants with live plants, both for the beauty and the Otos. <<Excellent idea :)>> We'll stick with making larger batches of tweaked water, and go get a cheapy air pump to aerate it (at least overnight) before we use it.  We're also talking about increasing the water changes to 20% a week rather than every two weeks, especially after reading about the sensitivity of Otos and Corys to nasties in the water. <<It would be a good idea to vacuum your substrate regularly, Corys are prone to bacterial infections of the barbels. Nasty stuff can accumulate in gravel beds, and Corys are always sticking their noses into...it. :P>> We're going to have to decide which Corydoras to get, since they prefer being with their own.  I'd had the impression that it wouldn't quite do to mix based on genus rather than species.  (Now if I can just convince my wife to go with the paleatus...) <<My favorite Corys are melanistius melanistius and adolfoi. You can check out pics of any species of Cory cat at www.planetcatfish.com/ Maybe you will both see something inspiring there that you agree on :)>> As I said in an earlier message, the little speed demon is, indeed, an Endler's.  He's started getting a stronger hint of green on his caudal fin, and a more definite green tinge on his rear half.  We're looking forward to getting a group of them after New Year's. <<Nice fish. Easy to keep and not a royal pain like so many livebearers can be...Belonesox spring to mind.>> Again, thanks for the wonderful site, and I hope I haven't chewed up too much of your time. Glen <<You are most welcome. Happy Fishing. LOL. -Gwen>>

Otos coloration: Sick or normal? I got four new Otos on Monday. Stupidly, I put them in my tank without first a quarantine (this won't happen again, trust me). I may just be paranoid but I am wondering about their coloration. It looks splotchy to me and I was wondering if this is normal or if it might be something I need to take care of.  < Hard to say what the problem is. It is normal for fish to have a fright pattern when being introduced into a new tank. As they begin to feel more comfortable than they start looking more normal. Many times these algae eaters are starved at the wholesalers and at the local store. I would place an algae wafer in the tank at night to make sure they are getting something to eat. If the splotchy pattern continues with all the fish or gets worse then I might start thinking there is a problem. -Chuck>  I am attaching two pictures. If you need any other details, please ask. Thank you for your time.  David

Breathless Oto (01/31/2004) Hi Sabrina or however gets to handle we freshies tonight. <Sabrina here!> Don here, from the "Needs Clarity" thread of inquest. <Good to hear from you again, Don.> Tank doing great, still clear as a bell. Plants growing well. <Ah, delightful!> Have not added any fish since the cycle completed and the water cleared. Still 8 Zebra Danios and one Oto in a 55 gallon with an Emperor 400 and one small power head. 0 ammonia and nitrite. 15ppm nitrate. Not bad since my treated tap reads .5, .5, 20. <Sheez, not bad at *all*!!  Plants are good things now, eh?> I have been doing 15 gallon water changes once a week.  Got a couple of quick questions, but the Big Story on Action New tonight is my sick or injured Oto. <Yikes.> I noticed a him breathing a little heavier than usual yesterday. When I got home from work tonight he was breathing much harder. I noticed a pink area just behind his eye at the top of the gill slit. He let me get a pretty close look and it seems that the pink is actual gill tissue. As if a piece of the gill cover was removed, exposing the gill. I could see it pulse in rhythm to his breathing. Only saw one side up close before he darted into his cave, but the other side was also pink. <Although this may be an injury, it might also be that the gills are irritated, and so more visible than usual.  Could be indicative of parasites in his gills; perhaps ich.> He's still in the 55. I have a 10 gallon I can QT him in, but the heater is inopt. I can pick one up tomorrow. <I would do so, if at all possible.> Just not sure what, if any, meds he should get. Still very active and feeding.  He pounces on his daily quarter algae wafer. Always working the glass and gravel. No spotting or other discoloration. No scratching. All fins seem perfect and extended, no clamping. He would be great if he could breath! <For now, perhaps all that is necessary is observation - but if this is parasitic, it could transfer to your other fish; best to quarantine him.> Now a couple of quick ones. What type of paint is aquarium safe and will adhere to PVC? I made some caves by coating PVC tubing with aquarium sealer and rolling them in dry gravel. They look good, but a little of the white still shows. Thought I'd paint the tube brown first to eliminate the white. <You could use a two-part epoxy paint, like such that is used for swimming pools and sealing plywood aquariums.> And finally, what kind of glue can I use to make slate caves? I made a few using the sealer, but it takes too long to cure. Had a couple collapse while drying overnight. <You might try a gel-type Cyanoacrylate superglue.> Don <Wishing you well,  -Sabrina>

Fish, Shrimp, and Thanks Our fish would like to say thank you to the WetWebMedia crew. (tank you, tanks, tanka) <To you and your fish - you're very welcome!  Please forgive the delay in response; I've been having computer issues, but it looks to be all sorted out now.> We have had a lot of fun with our new freshwater tank and several learning experiences. Our first fish was a "Betta in a bowl"  purchased by my two eldest, they saved their allowance to do this and we ended up with two new family members, Blootie a Betta, and Pickles, an African frog. A few months later we knew we wanted an actual aquarium so we soon had Blootie and Pickles housed in a ten gallon with five neon tetras, several plants, free snails which appeared out of nowhere and every thing was fine; we do a 20% water change weekly and add some aquarium salt and dechlorinator. <Sounds like great fun!  Please remember, when you add salt, only add enough to compensate for water you *remove*, not water that has evaporated, as salt does not evaporate.> Our tank is held at 78F and we have several plants which we prune every two weeks, we run a Whisper filter with activated carbon, every other week we switch the carbon for Ammocarb, though I am not sure it does anything, <Only the carbon is needed; test your water regularly for ammonia, with your water change/maintenance scheme, I doubt you see a trace of it.> we have a shallow smooth gravel substrate. We feed a mixture of flakes, bloodworms, brine shrimp and a pea every night about an hour before lights out. <Mmmmm, yummy!> Our first problems started when we obtained two new fishes, Odie and Sink (Otocinclus).  The primary pea consumer was Blootie but after Sink and Odie arrived things changed. Sink metamorphosed into a new fish we called Stink. He chased everybody, the tetras, the frog, the Betta and especially Odie, Odie lived in perpetual fear, Stink would charge the full length of the aquarium to get him. <WOW.  That does *not* sound like normal Oto behaviour!  Please check out the following links, perhaps you have something different....  First, on Otos: http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm  on SAEs (and non-SAEs): http://www.wetwebmedia.com/FWSubWebIndex/saes.htm > Stink actually latched on to Blootie a couple of times leaving a white mark which has now cleared up. <Yikes....> Stink may have been starving when he arrived but that passed, he turned into a very messy fish and was getting visibly fatter and  meaner. <He's sounding an awful lot like a "Flying Fox" or "Chinese Algae Eater" at this point....  notoriously mean buggars.> Pretty soon everybody started hanging out somewhere safe from the seriously deranged Stink and this caused problems, nobody was eating the pea, our water started to get cloudy and green algae started to grow on our floating plant. The tetras which previously tested every floating speck to see if it might be food, stopped doing that and spent their time up high, avoiding Sink. Blootie stayed at the top of the tank, ready to run, Stink couldn't eat all the food but he was determined to try. We finally decided Stink had to go and things are back to normal. Our water is clear again, nobody is chasing anyone and everyone seems happy. (We gave Stink to an unsuspecting local fish store, not telling them he was an insane fish.)   <*Laugh!*> I have been reading the freshwater links (I have actually been reading everything I can on your site as time allows) and my question has to do with adding a crustacean of some sort. We really do not want a repeat of the Stink trials and we really would like to add a shrimp or something. Given our current happy tank is there anything we could add that would probably be happy. <Stick with shrimps of the genera Caridina and/or Neocaridina; these primarily algae-eating lovelies include "the" algae-eating (aka "Amano") shrimp (Caridina japonica), cherry shrimp (Neocaridina denticulata), bumblebee shrimp (Neocaridina sp.), red-fronted or "Rudolph" shrimp (er, I think a Neocaridina specie....), red-tailed tiger shrimp (another Neocaridina), to name a few that are occasionally available in the US.  Ghost shrimp would be a safe addition, as well (and cheap, to boot - and commonly available).  Filter feeding shrimp, such as Singapore/bamboo/flower shrimp (Atyopsis moluccensis) are commonly available, and also perfectly safe to add to your tank; this last would probably be the most "fun", as they are large, diurnal, and uber-cool.  Stay away from "big-arm" shrimp of the genus Macrobrachium; these are nearly all carnivores that will prey upon your fish.  Same goes for crabs, they'll eat anything that holds still long enough - and some things that don't.> I have read about the shrimps in the freshwater shrimp section <Currently and unfortunately very lacking in information - I intend to rectify that with an article or two as soon as I dig up some time, I promise!> but I am still not satisfied that I won't get it wrong. <One important point - please dose the tank with iodine if you get shrimp.  This is easy and cheap.  Get a bottle of Kent Marine Iodine from your fish store (geared for saltwater tanks).  Ignore the directions on the bottle completely, as your freshwater shrimp have nowhere *near* the iodine needs of a saltwater tank - add only one drop of the iodine once every week (use a pipette or a medicine dropper from the pharmacy).  Doesn't sound like much, but it makes all the difference in the world.> In addition to adding a shrimp to our ten gallon, we intend to get another ten gallon aquarium and move the frog (Pickles) in with two fire newts, for which my oldest boy is saving his pennies, is this going to work ? <Oh, wow, I have absolutely no idea....  I'll pass this along to Gage for his input; hopefully he'll be able to help you on that one better than I can.> Thank You <You bet!  Wishing you and your critters well,  -Sabrina>

Otocinclus Meals Robert, <Hi, EJ, Sabrina here tonight, instead> I read your article on Otocinclus on wetwebmedia.com. Thanks. <Glad you enjoyed it!  I'm sure Bob appreciates the thank you greatly.> A couple questions:  In your article, you mentioned that they need wood to survive.  What kinds of North American woods are acceptable for Otocinclus?   <Pretty much anything that's been *very* well cleaned and either sinks on its own or is weighted will do.  Check out your LFS for driftwood ideas.> What state should the wood be in?  Fresh, weathered, decomposing, etc.?   <Very well weathered - as in, no bark remaining whatsoever.  Wood that is decomposing poses a problem as it will decay in the tank and make a genuine mess of things.> What is a good brand of sinking pellets to feed them?   <Frankly, my personal favorite dry food brand is Hikari, but I rarely (if ever) use algae wafers to feed my algae munchin' dudes.  Algae based frozen foods (Ocean Nutrition's Formula Two, for one example) are a good prepared food item to offer.> Will they feed on other vegetables besides the spinach, Nori, and peas you  mentioned? <Blanched cucumber and/or zucchini, perhaps the soft insides of green beans.... some years back, my Loricariids always appreciated the asparagus that I refused to eat as a kid....> Thank you very much. <You bet.  Wishing you well,  -Sabrina> EJ

You Say Po-toh-to, I Say Po-t-otto Do Otocinclus cats eat dark green Cyanobacteria in a FW tank? <Possibly, but are you sure you're dealing with Cyano?  It most certainly does happen in FW tanks, but plain ol' green algae is a likelier bet - and the Otos would most definitely chow down on that.  The best way to fight Cyano in a freshwater tank is to get some vascular plants to out-compete it; basically, the plants are more efficient, so they suck up nutrients before the algae can, so the algae misses out and dies off.  Myriophyllum, Anacharis/elodea, hornwort, or even a couple floating water lettuce would certainly help you in this battle.> Also what is the proper pronunciation of Otocinclus?  Like Otto-sin-klus or oh-to-sin-klus? <planetcatfish.com says "auto SINK luss".> Thanks! <Sure thing!  -Sabrina>

Otocinclus I just got a little Otocinclus which I planned to put in my 25 gallon aquarium. The aquarium has 2 goldfish, one a solid 5 inches long and the other smaller, maybe 4 inches long but most of which is a fan tail. I put the little Oto in, and got quite worried that they might eat him. This morning I found him in an impossibly small corner, just barely under water, where they could not get him.  My question is, should I take him out and keep him elsewhere until he is larger or will this always be an issue. Alternatively, will he be a good hider and I will be able to stop worrying. <The Oto really isn't a good fish to go in with Goldfish. The goldfish like cooler temps than the Oto and the Oto stays small enough that him getting eaten is always going to be a concern. Your best bet is going to be to put the Oto in a separate tank or return him to the store.> Also, the pet store said that one Oto would be fine, but I read this morning that they should be kept in groups. What is your advice? Thanks! Carol <They are much happier if kept in groups. Ronni>

Otos... Dear Crew, A little question  about the likelihood of the Otos in my planted freshwater tank breeding.  We have a four foot Juwel tank planted, with 6 Corys, 6 black widow tetras, 11 cardinals, 1 Sailfin Plec, 1 ram (we did have 3, sadly they were not healthy fish!), <Yes... the tank bred ones are proving less hardy than wild-caught in recent years> 4 red claw shrimp, and as far as we knew, 6 Otos, 2 flexilis, 4 affinis...except, yesterday, while doing a water change and gravel clean I noticed a very very small affinis, now I know that ours were all bigger, so is it likely that we have had babies? <Sure seems like it> I can't think of any other explanation apart from the catfish fairies! <Ha!> I thought that it was unlikely for them to survive in a community tank? <Mmm, too often, yes... but yours sounds like just the ticket> our water temp is 75-77, our ph between 6.5 and 7, we have very soft water 1-2 dKH (we top it up to keep it there, otherwise it drops lower), so have we magically done something right? <All the way around, yes> Thanks for any thoughts you might have on breeding Otos... Cheers, Nicola <Congratulations. Bob Fenner> Nicola Blay, BSc, MSc International Zoo Veterinary Group

Tiger barbs and Otocinclus I just brought home 3 Otocinclus and 1 twig catfish for my 29 gallon tank containing 4 tiger barbs.  The tigers are ganging up on the Otos and chasing them all over the tank.  I am worried that the stress will kill them!  They have not spotted the twig cat yet but I have just read that the twig cat is easily harassed.  These are the fish that were recommended by the aquarium store (Old Orchard Aquarium in Skokie, Illinois) knowing that I have the barbs.  I was going to buy a clown Pleco having read up on them.  The guy in the store said they were not good algae eaters and to get the twig cat instead.  I am ticked!  I don't want these fish to suffer but what if the store won't take them back tomorrow? <Hello, Tiger Barbs sure can be terrors.  If you provide plenty of cover and dark hiding places they should be ok.  Live plants are great.  If the tiger barbs do not ease up on them after a while you may want to consider removing the Otocinclus.  Please be sure that there is enough food to go around for the Otos and the twig catfish.  Have you checked out the article below, good stuff.  Best Regards,  Gage http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm>

Otocinclus Bob, I read your article in FAMA re: Otocinclus/S. American sucker mouth catfish..., and purchased 2 at a local pet shop. The salesperson said they were Chinese catfish, but they looked like the Oto pictured in your article. I want them for algae control in a 36 gallon tank with 3 mature Angel fish---2 egg laying females, and one male. I chose them as they seem to be more active than the Pleco species, and because they will make an "active" addition to the tank. Any suggestions...? Thanks. Dale Fox <Mmmm, suggestions re what? Enjoy them. Maybe give a read over the materials on the Freshwater sub web: http://www.wetwebmedia.com/FWSubWebIndex/fwsubwebindex.htm Bob Fenner>

Water Babies! (Otocinclus) Hi guys! Me again! <How cool is that.. I'm still me too <wink>! Anthony> My tropical tank has now been up and running for five weeks! The algae ****problem has been solved with the addition of the Otos (thanks for the tip, Anthony!)  <don't thank me...thank those wonderful Otocinclus catfish...hehe> Two weeks ago I added a pair of dwarf Ram Cichlids.  <lovely but shy creatures> On Tuesday (26th) I watched as the female laid eggs on a leaf and the male fertilized them - fascinating!  <you have been blessed!> The male now seems to guard the eggs while the female swans off around the tank (if only this was the case in the human world). <you do recall that this is a male dominated hobby, my dear? hehe... try to sell this one to the union! Ha!> Anyway, I was wondering how long it would be before the eggs hatched.  <a matter of days dependant on temperature> I have read quite a few books but nowhere does it say how long it takes for the eggs to hatch. Also, do these fish guard their fry once hatched or are they left to their own devices? <no...parental guarding, but don't expect much in a community tank.> Also, I appear to have a few baby fish in the tank which have mysteriously appeared!  < a livebearer no doubt> These babies look suspiciously platy-like but on reading your FAQs and articles I understand that platies get fat and go transparent in their vent areas before giving birth. None of my 7 platies are or were fat and none of them appeared to have transparent areas. I certainly did not see any baby fish eyes inside them. I have had the platies for four weeks and these babies are coming from somewhere!  <if you don't have another live bearing species it was one of the platies> Currently, they are hiding in the moss and I am trying to feed them using crunched up pellets, crunched up flakes and frozen and live daphnia. Not surprisingly, they are not terribly forthcoming at feeding time. Is there anything else I can do to help them survive?  <short of separating them, bushy floating plants (plastic or live)> I am aware that they may not live for very long in a tank with greedy platies and guppies! I think my cardinal tetras are the only fish not big enough to eat them! Finally, survivability issues aside, I am wondering if overcrowding could become an issue (depending upon the number of survivors - I include both the platy babies and potential rams here). Do I have to keep getting bigger and bigger tanks each time I become a parent?  <if you don't eat fish, you do> I can see the little dears eating me out of house and home in no time! <you may want to be more selective about the sexes... remove a gender as it were <boo>> My aquarium is planted but I will be getting some more plants (hopefully water sprite) this weekend to add additional hidey holes for the new arrivals. Any information you could provide regarding my babies would be much appreciated! <yes... build a 400 gallon tropical fish pond in your basement <wink>> Many thanks! Lesley <quite welcome. Anthony>

Species identification of Otos Dear Mr. Fenner, I have been examining many sites on the internet in hopes of answering some questions I have concerning Otos. In every site, almost every picture was similar, but each had a different species name attached. How can I tell them apart? I have what I believe is a Paraotocinclus, and two Otos. The Otos I'm sure of, however, not in species identification. Where can I get help in differentiation? <About the best on-line source (bibliographic) here is fishbase.org... my print bibliography on these species of Loricariids can be found here: http://www.wetwebmedia.com/otosagb.htm Bob Fenner> B. Jurich

Otocinclus Hello Bob, have heard a lot about you from folks at SDMAS here in San Diego. <Maybe see you later tonight> My gig is working on breeding marine ornamentals but I saw your article on the "little suckers" in FAMA and thought I'd use the excuse to introduce myself. I had never head of the fish until a few months ago, I helped a friend set up a fresh water planted tank and came across them. Gotta say I love 'em. I have a small backyard pond (300 gals) and was wondering how they might do in there. Temps are in the high 50's right now, but I thought as spring came on I could introduce some, maybe twenty or so. Do you think they could handle So. Cal. temps year round if acclimated? <Not all year round, no... could be kept outdoors maybe four, five months out of the year... but would insert a thermostatic heater... set low... for safety's sake> I've got some small Koi and pond comets (no surprise) but what stuns me is that there are a number of zebra Danios and white clouds that came in with "feeder" guppies I threw in there during the summer. To my surprise the guppies died out as the weather got colder in December but the zebras and white clouds seem fine! I know you're a busy guy but if you have a moment let me know what you think. ...David <These are tough little minnows. Have had them outdoors (nearer the coast) in large enough, weather-sheltered ponds in San Diego as well. Be seeing, chatting with you. Bob Fenner, WetWebMedia>

Re: Daily Fish Email out WWM Can you identify this species of "Oto" (Otocinclus or similar genus) catfish? A beauty... at Singapore's Aquarama this year. Sorry, don't know them as well as you. This time of year fish take a back seat to that most robust of birds. Its too bad that we don't have a holiday that celebrates the FISH. <Should though... have been through my print references re this species... and another or two that I'll post in succeeding days... they're under commercial production in the "far East"... Seems odd to not find at least an i.d.... Gobble, gobble, Bobble>

Illnesses with Oto Dear Robert, I actually have two questions. We recently bought 2 Otocinclus flexilis and they initially did well. However after about 1 week, one died and the other has stopped eating. Our water tends to run on the alkaline side but never higher than 7.6-7.8, <Otocinclus spp. don't care for hard, alkaline water... this or the stress/damage from collection, shipping could easily account for what you have observed> I tested the nitrites (zero), I generally do 25% water changes every week, no further apart than 2 weeks. We have 8 other fish in the tank (20 gallons) 3 upside-down catfish, 2 swordtails and 3 bleeding heart tetras. Of note, one of our swordtails was incredibly sick approx 1 year ago. We managed to nurse him back to health with 14 days of gram positive and gram negative antibiotic coverage as well as with CopperSafe (all in a quarantine tank). Since then, he has been fine. About 2 months ago, one of our tetras began swimming erratically (nose pointed upward, tail pointed down and appears to be frantically swimming but no getting anywhere.) He was moved to the quarantine tank as well. He's gotten a bit better (now he eats) but he still swims funny and now his tail is all frayed. I treated him for 14 days as well with Maracyn 1 and 2 and CopperSafe. (I've continued the CopperSafe). So, the two questions are: what's wrong with our bleeding heart tetra and did the Oto's get what he had (he had been out of main tank for nearly 1 month before we added the 2 Oto's) <This all sounds a bit eerie...> Also, I just read your article on the web and noticed that CopperSafe can do more harm than good to these guys. The Oto died today. I had added CopperSafe and Maracyn 1 and 2 to the tank this AM after noticing that both were acting sick (he was worse than his buddy). Did I kill him with the CopperSafe? <Likely this contributed to the loss> Thanks for whatever help you can offer. Brigitte Baumann <I would have your source water checked (by the supplying agency, a quality assurance lab...) and likely get/use a filtration system for your pet-fish as well as drinking and cooking uses... Please do look into a reverse osmosis unit... inexpensive, easily maintained. Bob Fenner>

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