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FAQs on Feeding Feeder Goldfish, Guppies

Related Articles: Feeding "Feeder" Goldfish by Bob Fenner, The Feeder Fish Debate: Are They Essential, Cruel, Or Dangerous?  by Neale Monks, Thiaminase and It's Role In Predatory Pet-fish (& Other Piscivores) Nutrition, by Marco Lichtenberger, Culturing Food Organisms,

Related FAQs: Brine ShrimpAlgae as Food, VitaminsFeeding Lionfishes, Frozen Foods, Culturing Food Organisms

A Red Lionhead Goldfish, same species as the Comet.


Fish lice and American freshwater eel (RMF, anything to add?)      8/28/17
Hello, I have an American freshwater eel that I bought at a Maryland bait shop about 5 years ago.
<Interesting fish, T! Kept a European Eel years ago, and it was quite a beast!>
Although shy, he has been doing well.
<Anguilla species are generally extremely robust but fundamentally nocturnal, which accords well with what you've seen. The biggest obstacle to success is escape, because they do have a very strong migratory instinct.>
Just the other day I brought home a dozen comets to feed him, and only noticed a day later that one of the feeders had fish lice.
<***Sound of Neale bashing his head against the wall***>
(lots of Google searching there) I got out 3, 1 swimming and 2 on the feeder, but found a line of what looked like eggs that I was unsuccessful at removing.
<Oh dear.>
( they swirled away. oops.) I am worried what I can use to treat the tank with that would be safe for my eel.
<Prevention better than cure, here. To recap for the benefit of our readers, there is NO reason at all to use "feeder fish" when feeding virtually any aquarium fish. As our correspondent here has learned, it's a good way to introduce disease. Furthermore, goldfish are rich in Thiaminase and fat, two things that cause health issues in pet fish. Anguilla species hunt by smell, and from personal experience I can tell you they'll eat anything, even strips of fish fillet and squid. No need for live food, except perhaps earthworms and river shrimp while acclimating new specimens to life in captivity.>
Or if goldfish lice can even spread to an eel?
<Probably. Fish lice (Argulus spp.) are certainly known from Anguilla spp., so the balance of probability is that this is a real danger.>
I think copper is supposed to be bad?
<Copper is toxic to virtually all life; it's really a question of how much.
The "art" is dosing enough to kill the pathogen without killing the patient. In this case, copper isn't really your best option. There are really two good solutions here. On fish farms, you'd simply move the fish into strongly brackish or marine conditions. That'd kill the external parasites without much trouble. Anguilla spp are euryhaline, but once
acclimated to brackish or marine conditions, chances are it'd go into its reproduction mode, changing from its current yellow eel phase into the breeding silver eel phase. Keeping such eels in aquaria is very difficult because they will desperately try to escape, even if it means they need to hit you over the head and steal the car keys to do so. Your second option is a suitable insecticide (typically organophosphates) though Fish Lice are, of course, crustaceans. Using these organophosphates is potentially risky because they are highly toxic, so you need to follow the instructions provided by the manufacturer or vet very carefully. As far as I know, copper is not toxic to Argulus at levels safe for your fish, which is why treating Argulus on ornamental fish is such a headache. It's primarily pond people who have to deal with it; for some reason it doesn't often become established in aquaria. Of course if you introduce pond fish (like "feeders") to an aquarium, then all bets are off, and Fish Lice can become
a serious headache. They are difficult to deal with, severely harm the host, and the wounds they create quickly become infected with Aeromonas and Pseudomonas infections.>
And a salt soak would not clear out the rest of the tank.
<Not sure what you mean here. Run the tank as moderately brackish to marine, and yes, Argulus will die. Standard operating practice on salmon farms.>
Research has not given me much as most people have marine eels or spiny eels.
<Oh, wow, there's tonnes of research into Argulus if you check out the academic literature. It is potentially a massive threat to commercial fish farms. Koi keepers also deal with it on a regular basis IF they don't quarantine new livestock, and organophosphate medications are available for treating pond fish -- you'll need to use one of those, unless you have a local vet able to help you. Regardless, organophosphates should work well, but Anguilla are unusual, and organophosphates are acutely toxic, so do carefully observe your eel for signs of distress. I'd have some good quality carbon handy in case something goes wrong -- at the first sign of distress, do a massive (~90%) water change, followed by filtering through carbon (or some similar marine-grade chemical adsorbent) together with increased water current and aeration.>
Can you give me any advice?
<Don't use feeders, EVER.>

Thank you, T
<Most welcome. Cheers, Neale. PS. BobF's our pond guru, so I'm going to ask him to chip in if I've missed anything.><Nada mas Neale. Excellent resp. by you as always. B>

Joining request and bait fish question      7/1/16
Hi crew
I have been following the email threads and asking a few questions of my own for quite some time and have been in the hobby for a very long time, mainly with monster fish such as alligator gars, Arowana, mainly silvers, blacks and Australians but have also dealt with the African Arowana, red tailed catfish and its hybrid, large South American cichlids and freshwater stingrays. I currently have most of the above as well. Not sure if you have room for me but I feel like my experiences and tips and knowledge I have gained can help out other people as well.
<Do you have a brief resume, list of pertinent experiences we might share around?>
I also have a question regarding baitfish, such as the shiner.

Pteronotropis signipinnis to be exact. I do not have the space to breed in house feeders for my obligate piscivores so I have been using a wide range of bait fish since goldfish and rosy red minnows are fatty and contain thiaminase. However I was wondering if the bait fish carry that as well. I gut loaf <load likely> the feeders with Hikari before feeding them off but was wondering if these were a safe long term option. Thanks Ian
<Am a much bigger fan of using whole marine fishes of small size, or even fillets of larger ones for predatory freshwater fishes, rather than freshwater minnows... for the Vitamin B issue you mention as well as the possibility of pathogenic disease transmission, induced aggression....

Please see WWM re feeding Osteoglossids, Phractocephalus et al. for much more useful input here. Bob Fenner>
Re: Joining request       7/2/16

I used to run a monster fish rescue specializing with Arapaima for about 5 years and then had to close it down due to having to move and not being able to have as many pools up. I rescued a group of tiger fish about a month ago. They are in one of my holding systems now until they can go somewhere where they can be housed permanently. Anything that is big, mean or toothy I have dealt with and kept. I have been able to wean things onto dead or pellet foods that most people cant. For example my leaf fish are not on live but pellet. They were imports. I am a monster fish keeper member and also belong to the CCA. I built my Amazon display tank myself, tank filter and all. I believe I am qualified enough to join your crew if there is room for me. Thanks Ian
<These are all bold statements; do you have links, proof that will show your association to these activities? BobF>
Re: Joining request       7/2/16

Hello Bob, Ian,
<Cheers Neale>
More than happy to welcome another FW aquarist to the crew! Especially anyone who can wean Leaffish onto pellets!
<Ahh! We'll give you a go then Ian:
Our email log in:
The group name:
Some conventions we use in responding are detailed here:
Please review this last before responding; as the formatting consistency is important in serving our readership.
Welcome to our association. Bob Fenner>
Cheers, Neale

Cephalopholis fdg. SW issues from FW comets?      9/4/13
I have an 11-year-old Miniatus Grouper that I occasionally feed live freshwater feeder fish
<A poor idea... Thiaminase, fatty issues... and more>

to.  90% of the time I feed frozen silversides, krill, etc.  I was recently told by another saltwater hobbyist that my grouper could get internal parasites from feeding him/her the freshwater feeder fish.  I know external parasites wouldn't be an issue, but what about internal parasites?
<Good question (among other reasons; I don't know). The worm issues I'm familiar with tend to be fresh or marine specific...>
 And what treatment could I provide to eliminate them if this really is a risk?
<Likely the usual mixed in antiprotozoal (Metronidazole) and anthelminthic (my choice would be Praziquantel) would "do it">
I have decided to not feed live feeders anymore.
<Ah, good>
 Thanks for any information/advice.
<Thank you for your query. Bob Fenner>

res strange behavior, feeders...   6/19/2013
I recently feed my six year old female res feeder fish. After I put them in the tank I left for an hour. When I came back my res was swimming in circles, not moving its head up or down. It was dragging it along the ground. I placed on the basking dock and it just sits there lethargic with its head laid out and eyes closed when I touch its legs it flinches, but when I touch its head it does not  move. Any thoughts? Thanks
<Thoughts? Yes, along the lines of "why on Earth were you feeding your turtle feeder fish"?! Let's be clear, feeder fish are parasite time bombs, and furthermore, since your turtle species is more or less a herbivore as an adult, you should be paying more attention to green foods if you want to offer it something different to dried turtle food-sticks. In any case, assuming it's not behaving normally now, you need to rush this turtle to your nearest vet for a check-up. The sorts of diseases that come from feeder fish aren't ones that get better by themselves. There's also the risk of a bone stuck in its throat, which again, isn't something you could fix. Regards, Neale.>

Sick Oscars, feeders...      11/20/12
We have two Oscars.  One is a Tiger Oscar the other is an Albino Tiger Oscar.  They are both about 6 months old.  We got them at the same time, when they were about the size of a quarter each.  They have been absolutely fine and we love them.  We have a 90 gallon tank and we keep it impeccably clean!  Nitrates - 0,
<Do you mean nitrites? With an "I"? Nitrates, NO3... are, what?>
Ammonia - 0, PH good.  We vacuum their poop out every weekend and I check water quality daily with test strips.  Last weekend we did the normal gravel clean and poop vacuuming and adding of new fresh conditioned water. 
We did remove two coral decorations, as they Oscars are getting larger and they are skinning themselves on it while attempting to chase feeder fish. 
<Aye yi, yi... VERY dangerous to feed such... these are assured vectors of infectious and parasitic diseases. Read here:

and here: http://www.wetwebmedia.com/FWSubWebIndex/oscarfdgfaqs.htm
Sunday night when I turned on the room light, the fish thrashed and flipped and flopped and went crazy in the tank.  They scrapped themselves on the gravel and knocked large hunks out of their heads!  I went to the aquarium and looked at them and I thought they were sleeping, because they have a dazed look.  I shut off light and left them alone.  Next morning, they did the same thing!  I checked the quality of the water and it checked perfect, as always.  We went to work.  Husband came home and noon to check on them and said they seemed lethargic, so he gave them a few feeders
and put one of the coral formations back in the tank, thinking that they missed it and were throwing a fit (???).  Monday when we got home from work, they seemed better, but hiding behind the coral formation.  I again checked the water and it was great.  Temperature about 78 degrees.  Last night in the middle of the night, it was dark in the house, I turned on the room light and they did it again!  Thrashed around, splashed water all over, thrashed around like having convulsions.  I do not know what is wrong with them!  I called my local pet stores / aquarium store and investigated online.  All stories relate to problems with water.  That is not an issue here.
Could it be the feeder fish?
<Ah yes>
  We got a fresh batch on Sunday and the crazy symptoms started then.  The feeders seems very healthy.
<They are not. I am an old timey fish health/pathology speaker/presenter at college workshops... and have used "feeders" for decades as stock dissection specimens... they always have substantial pathogen loads>

  Their water is checked constantly as well, with no nitrates and no ammonia.
Any ideas what is going on?
<Yes; likely a few Protozoans, perhaps some alimentary worms, even some secondary infectious agents... You should peruse WWM re Oscar Diseases... they're all covered on the site... you'll have to treat for each/all... and give up re-introducing disease causing agents via live feeders>
 Could they be mating at 6 months old?  I have decided to dump the feeder fish out of an abundance of caution and withhold  food completely for a day or so and see if symptoms go away.  I read somewhere to try feeding them green peas.
What do you suggest?   Please write back with any comments or helpful suggestions.  We are stumped.
Thanks so much!
Joanie Clendenning
<... start here: http://www.wetwebmedia.com/FWSubWebIndex/OscarDisF12.htm
the linked (category) FAQs above... Bob Fenner>
Re: Sick Oscars

Thank you so much.   My husband went home and noon to check on Oscar and Edgar and they have stopped eating the feeder fish.  He gave dry pellets and Edgar ate, but Oscar is very finicky and spit it out.  I'll try other things tonight when I get home.  THANK YOU VERY MUCH!!!
<Welcome... but do read where you've been referred... BobF>
Re: Sick Oscars     11/20/12

Yes, I am checking that all out right now.  Thanks again!
<Real good. B>

Marine Betta Experience, fdg., training live-food-only fishes    4/25/12
About 8 months ago, I purchased a Marine Betta, and found getting him to eat anything but live foods to be quite a challenge.
<Often the case w/ Plesiopsids>
 I did a lot of
research, including on your website on feeding them. I thought I would share my experience because he is now trained on New Life Spectrum pellets, because others would likely welcome the same information.
<Ahh, I thank you>
I started by feeding him enriched live shrimp, with the goal of weaning him off as soon as possible. The first tip I would have is not to spoil them.

I made this mistake early on when feeding him live foods too often. I then decided to try frozen Mysis, which he would not touch. I fed this to my fish about twice a week and covered it in a garlic supplement. He would not touch it until I used the garlic additive. He then tried it a few times, and spit it out. But after a week of that, he finally ate the frozen stuff.
I then included frozen Mysis and the new life spectrum pellets. Again, I tried the garlic supplement (I think it was called GVH fish food soak). In about two more weeks, after alternating frozen Mysis and new life spectrum, he finally started eating the pellets. I know where he hides in the take, so I put the pellets in a stream of water where the pellets would end up in front of him. Before long, he would come out when I fed the other fish. He will only eat the large pellets, while the other fish eat the smaller ones.
He is now fully trained on the pellets.
<Ah good>
I will say, I have had lionfish in the past, and training him was similar to them. He will also go on periodic hunger strikes, much like they will.
Although he hides a lot, those periods where he comes out make having him worth it.
Hope this helps someone,
<Indeed. Many others. Bob Fenner>

Leopard Bush Fish and Ich Treatment 6/28/2011
Hi Neale,
Hope you are doing well. May I bend your ear again, please?
This is in regards to a Leopard African Bush fish I just acquired. He is a really neat fish.
<Ctenopoma acutirostre, one of my absolute favourite fish.>
To my dismay, I got some feeder fish at the LFS, one that is supposed to be better then most, and after having them in his quarantine tank for a few hours, I noticed they had Ich.
<Par for the course'¦>
Now I know why I have never purchased feeder fish in the past. Needless to say, I am so upset! I quickly took them out of his quarantine tank and started the salt, heat treatment, assuming he will get Ich now. My question is, will this fish be okay using the heat and salt treatment?
<Yes. Over the short term, Climbing Perch generally are extremely tolerant and adaptable. Few live in brackish water (Anabas spp. are the only ones, to the best of my knowledge) but they will all tolerate the low salt levels used to treat Ick.>
I researched and can't find any information on how they do with salt. It is really disturbing to me that I can't find one fish place in my area that does not have dead or sick fish. Thank goodness I quarantine my fish! Thanks Neale, for your help, as always. Cheers, Luanne
<There's no need to feed this predator feeder fish; their diet is very mixed in the wild, and includes large amounts of insect larvae such as bloodworms. A few take pellet foods, but most specimens are easily maintained on a mix of wet-frozen foods plus chopped seafood and tilapia fillet. Earthworms are a good treat! Cheers, Neale.>
Re: Leopard Bush Fish and Ich Treatment    6/29/11
Thanks so much Neale, check him out, what a handsome fish!
<Glad to help. Handsome fish indeed! Cheers, Neale.>

Dear WWM, I was wondering  6/21/10
Dear WWM, I was wondering what the best type of food for a Jack Dempsey is worms, pellets or feeder fish?
<Do not ever use feeder fish. These are "parasite bombs" that will eventually make your fish sick. Cyprinids such as goldfish and minnows also contain fat and thiaminase that causes nutritional problems. Good quality flake or pellet food, e.g., Hikari Cichlid Gold, makes a fine staple.
Augment with earthworms, small pieces of tilapia fillet, and chopped seafood as you prefer. Cheers, Neale.>
Dear WWM, if I have
Dear WWM, if I have 2 Jack Dempseys will having feeder fish in the tank
increase or decrease there aggression toward each other
<The use of feeder fish tends to make fish MORE aggressive. The use of feeder fish is also unsafe, unhealthy, and inhumane. There are NO GOOD REASONS to use feeder fish. Cheers, Neale.>

Anti Feeder Fish Coalition   6/3/10
> Hi Bob,
> Have you seen this?
<I had not>
> http://www.youtube.com/watch?v=FybGYCwUyLM
Well done to the American Cichlid Association for making this point. Let's hope the message gets through to US pet stores that feeder fish are risky, unnecessary and cruel.
<A shot toward that direction. B>
Cheers, Neale

Re: Hoping to add GSP, foods, live fish as foods,  3/10/10
Thank You so much for the speedy reply, was not expecting that. Wow, where to begin. I completely agree, back to the drawing board it is.
<Indeed! But happy to help.>
Just to verify, it is an moral question when it comes to feeding live fish, is it not?
<Both. In terms of morals, it's certainly cruel and unfair on the prey. In the wild prey animals have space enough to avoid predators most of the time, something that doesn't happen in an aquarium. Also, wild versions of Goldfish and Guppies are not deformed, so they have subdued colours for camouflage, and the right shape for swimming, neither of which holds true for the farmed versions of these fish. Finally, we don't really know whether death by ingestion is painless or not, and there's science either way when it comes to whether fish can feel pain or not. Almost no predatory fish in the hobby needs live fish as food. So all things considered, it's morally difficult to justify feeding live fish to most predators.>
Or do you advise against it for some other reason?
<Yes. There are several practical issues. Firstly, cheap "feeders" commonly introduce parasites. Anything cheap enough to be a feeder won't have received much in terms of healthcare or water quality. Secondly, certain feeders (specifically Goldfish and Minnows) contain thiaminase and large amounts of fat. Thiaminase leads to Vitamin B1 deficiency, and there's ample evidence now that this is a major problem for predators in the wild and in captivity. Bob Fenner has established that *the* major cause of premature mortality among Lionfish is the use of Goldfish as feeders, with all the specimens he's autopsied having unnatural amounts of fat around the internal organs. Finally, there seems to be a link between aggression and the use of live food, with the predators that settle best into community systems being the ones fed fresh or frozen foods instead. In short, if you can get a predator onto non-live foods, you're not only going to save massive amounts of time and money, but you'll also be providing a better, healthier diet. To the folks who think they're losing half the fun, let them instead concentrate on teaching their predators to become hand tame.
My Ctenolucius gar for example feed from forceps, and that way I can show off what a good fishkeeper I am whenever people come to visit!>
I guess it makes sense that even once the puffer has had its fill he would bother the ones that weren't lunch.
<Actually, animals, especially puffers (and of course humans too!) will eat much more in one sitting than they need to. Overfed puffers put a tremendous strain on the filtration system, with issues such as nitrate levels and background acidification coming into play. It's best to feed modestly, small amounts, perhaps daily, perhaps less often when the fish is mature.>
It seems that I'll be needing another tank.
<For GSPs, yes. They're best kept alone, with their own kind, or in a tank that might ultimately be converted to a marine system so you can add Damselfish.>
My thoughts were, to escape the issues involved with the commercially sold feeders, rosy reds, comet goldfish, etc, such as diseased unhealthy fish, that I would try to breed my own.
<Almost never worth bothering with. By all means have a tank of snails in the yard, and use these as often as you want. But don't go out of your way here. You can maintain pufferfish perfectly well on foods from the grocery store. Unshelled shrimp, squid, cockles, tilapia fillet and so on all make good staples. Do read Marco Lichtenberger's excellent piece of thiaminase though, so you can choose the right seafood:
You want to limit thiaminase-containing foods to the minority portion of the diet.>
Guppies because of the quick reproduction and hardiness of the fish, as well as their tolerance of salt when introduced gradually to their existing freshwater tank, and their ability to live in brackish water.
<This is true, but fancy Guppies are less productive than wild Guppies, and neither matches Mosquitofish. In any case, you won't be able to produce these in anything like the numbers you're imagining.>
I am willing to do what it takes to keep all of my fish happy and healthy, including the ones intended as feeders, however short or long they would be living in my tank. And as you said, the one cheap enough to feed are kept in dismal conditions.
My guppies were kept in our community tanks under prime conditions, not the feeder tanks, which is why I would feel safer feeding them to the puffers than the feeder tank fish, which unfortunately are kept under fairly dismal conditions, mainly massive overcrowding =(. I didn't design the store, I just work there. I thought maybe the guppies outnumbering the puffers would make it possible for them to still breed, but I thought wrong lol.
<I fear so, unless the tank was 1000 gallons! I've seen Guppies kept with Piranhas in zoos, but beyond that sort of scale, this just doesn't work.
It's been tried many, many times.>
What would you recommend for feeding puffers than if not live fish.
<For juveniles, wet-frozen krill, Mysis, chopped cockle and mussel, and things like the legs from unshelled shrimps are all ideal. Woodlice (what Americans call Roly-polys I believe) also go down well, and of course any snails of suitable size, such as Physa spp. Adults will eat much the same thing, but for economy's sake you'll probably want to scale up to chunky fish and seafood: cockles, mussels, squid, crab legs, whole shrimp, tilapia fillet, etc. Again, snails of suitable size are good. There are some puffers that take dried foods like algae wafers and marine fish chips, so you might try these, but generally flake and pellets are ignored (though two of my six puffers enjoy Hikari Cichlid Gold).>
I've seen it all over the web that brine shrimp are appropriate (explanation, not defence of the issue),
<Baby brine shrimp (nauplii) are excellent, but adult brine shrimp contain very little in terms of vitamins. You can buy wet-frozen fortified brine shrimp that have vitamins added, and these would be a good addition to the diet of any fish.>
as well as thousands of videos of puffers eating live food, but obviously you can't trust everything you see. As I said I get all the Ramshorn snails that I want for free.
<Well they're excellent, so long as they're from a fish-free pond. Anything collected from a pond with fish runs the risk of introducing internal parasites.>
As to why GSP, we had some come into the store for adoption and I fell in love.
<They are lovely fish, to be sure.>
They were used to freshwater, coming from Wal**rt, but didn't seem to be doing to well in our tanks, low ph I think.
<Likely so, or something similar.>
I was planning on bringing them home but unfortunately they didn't make it at the store. I don't know about where you are, but here they are always sold acclimated to freshwater, and I wanted to give them a chance to thrive by slowly moving them over to brackish.
<Sometimes sold as "freshwater" fish here too, but thankfully not by the better shops.>
As you said these fish are full of personality, and they stuck in my head from the moment I saw them.
I am dreadfully sorry about the small amount of knowledge that I have coming from the LFS. I am new there, but I wouldn't say that anyone has any more knowledge than myself at the store.
<I'm glad you've established your niche and you're willing to work at it. I hope you'll be able to share your knowledge with your colleagues and your customers.>
What would be some good staples to read so that I can educate myself and my coworkers in the fish we sell (all freshwater, mollies, platys, guoramis, goldfish, Plecos, swords, etc. as well as African, Oscar, blood parrot, and just recently flame mouth cichlids.)
<We do have a listing of books that those of us here at WWM have found useful and recommend to others, here:
Unfortunately the store has a habit of hiring folks off the street with very little experience and then training them, but I feel our training should be much more extensive.
<I agree.>
I will be speaking to my GM about possibly requiring some sort of outside training beyond what corporate sends us.
<There *are* courses for tropical fish shop specialists out there, at least here in the UK, and the shops often display certificates to show that their staff have completed these courses and "raised their game" to the next level. That's something I think reflects well on any store.>
Thanks again, cruising your site as you read,
<Glad to help. Enjoy your fishkeeping and your work! Cheers, Neale.>

Scales are missing on Red Tiger Oscars 2/1/2010
<Hello Denise,>
My son and daughter each have a small Red Tiger Oscar.
<Bad choices as pets for children. These are very difficult fish to keep properly.>
The Oscars are kept in separate 5 gallon tanks with filters.
<Insane. Make that 55 gallons for each tank, and we're talking.
Five gallons is barely enough for a Betta, let alone an Oscar. Did you tell the pet store you were doing this? If they told you that was fine, then they're idiots. If it was your idea, and somehow you though they'd be fine for a while, then, well...>
They are fed 2 small gold fish feeders every other day and flakes on the other days.
<Did you read ANYTHING about Oscars before purchase? If you did, you'd known feeder Goldfish are a VERY BAD food item for Oscars. Not only are they a major source of parasites, they're also loaded with fat and thiaminase.
We have done the water changes and de-chlorinated the water. Lately we have been noticing that each of the Oscars seem to have white spots, but more like the scales are missing, not like Ick. I thought they may be scraping themselves on the gravel but we never see them do that and it is getting worse. Any ideas?
<Yes. You're killing these fish. Whether deliberately or through sheer ignorance, you've stuck two perfectly nice animals in enclosures they cannot possibly be maintained in, and then fed them the worst possible diet. So these lovely, intelligent animals are being poisoned to death.>
Denise F
<Denise, I really, really do not like yelling at people. And when people write back that their feelings are hurt because I've yelled at them, that's sad. I volunteer here precisely because I like fish and I like people. But
when I get messages like this, it's hard for me to return a measured, let alone kind, response. Not one aquarium book ever written would ever suggest keeping Oscars this way, so my only conclusion has to be you read nothing
at all before buying these animals. Given you haven't said anything about water quality, I have to assume you didn't cycle the tank for 6 weeks before adding the fish. So essentially everything that you could do wrong, you have done wrong. It's not the fish's fault, it's not the retailer's fault, and it's certainly not my fault; it's your fault. Time to read what I've sent you to, think about what you've done, and react accordingly.
These fish aren't going to survive these tanks, let alone get better.
Either return them or euthanise them.
If you want to keep them, you're going to need a 55 gallon tank for each one, or a 75-100 gallon tank for the two of them. Don't delude yourself into getting a 20 gallon tank now, and then saying you're going to upgrade in a couple months. These fish grow EXTREMELY fast when kept properly, and will need that 55 gallon tank within 6-9 months of hatching. So get real, focus on what needs to be done, and move on. Feel free to write back and
yell at me for being rude if that makes you feed better. But my concern here is for your fish, and the bad example it's setting your kids. Cheers, Neale.>

Re: scales are missing on Red Tiger Oscars, hlth., nutr.  -- 02/02/10
Hello Neale:
<Hello Denise,>
My apologies for my ignorance. I did tell the pet store exactly my plans and purchased the Oscars at the same place. The same place I buy the feeders. Obviously they were either only concerned with the sale or they had less knowledge than I did.
<Well, you do have to treat advice from store clerks with caution. Some specialist retailers are staffed by outstanding fishkeepers, and I've learned a lot by listening to them. But all too often the generic pet stores employ staff who know little to nothing about fish. In general, take the advice, but double check against a book or a web site you can really trust.>
Many years ago, I too had an Oscar for many years, fed him feeder fish and never had a problem.
<It's like the old maxim, "playing Russian Roulette once and surviving doesn't make it safe". Work on predatory fish has demonstrated without any ambiguity that diets high in thiaminase lead to ill health and premature mortality. Do read Marco Lichtenberger's piece here at WWM on this topic.
The incidence of parasite infections following the use of cheaply produced feeder fish is very high. Furthermore, goldfish and minnows are rich in both fat and thiaminase, and Bob Fenner believes, after autopsies of numerous fish, that these feeder fish are the #1 cause of premature death of Lionfish. The #1 cause! These feeders are killing more Lionfish than bad water quality! Thankfully, feeder fish simply aren't sold in the UK, so this isn't an issue here. The hobby has moved on, and aquarists switched to safer, cheaper, and less expensive foods. But for whatever reason, the US market has changed yet.>
Never did the pet store say anything about having a 55 gallon tank, nor did they tell me about feeder fish being bad for them to eat.
<Not impressed by them, I have to say.>
Once we started noticing the problem. We immediately began the water changes every 3 days between 25 - 30%. We are now feeding them frozen, thawed shrimp and peas.
<Again, do go back and read about thiaminase. Shrimp contains a lot of thiaminase, and over time, over-use will lead to vitamin B1 deficiency. I'm sure you already know about how the Royal Navy was plagued with the problem
of scurvy back in the 18th century. The sailors were getting lots of calories, but for some reason would get sick within a few months of leaving harbour. The problem was that their diet, while adequate in other ways, lacked vitamin C. Over time this meant they became sick. Only with the introduction of citrus fruits into the sailors' rations did things improve (from whence comes the nickname for the British around the former Empire, "Limeys"). It's precisely the same thing here: shrimp, mussels, clams, squid and other thiaminase-rich fish and seafood may contain lots of calories and protein, but they also contain thiaminase, and over time, you're creating problems by using them. Restrict thiaminase-rich foods to once or twice per week. The rest of the week should be made up of foods
that lack thiaminase. These include good quality pellets (e.g., Hikari Cichlid Gold), earthworms, snails, fresh or frozen cockles, fresh or frozen tilapia fillet, and of course plant foods like cooked peas. Indeed, a perfectly adequate diet could be based around just good quality pellets plus the cooked peas to ensure adequate fibre.>
I have done a lot of reading over the past few days and the Oscars seem to be improving dramatically.
In addition we are currently looking into a 55 gal tank.
<That's fine for one Oscar; two will eventually fight in that space, unless by some miracle you have two females, or else a pair that get along from the word go.>
I thank you and appreciate your advice no matter how loud you were yelling.
<Glad to have helped. Good luck. Cheers, Neale.>

Fuzzy Dwarf Lionfish (RMF, are there "safe" feeders for marines?)<Yes; of marine origin.> 12/10/09
hello, my fuzzy dwarf lionfish that I've had for about four months is suddenly loosing his color.
<Oh? Fish maintain their colour via foodstuffs, primarily carotenoids in crustaceans and various other substances in algae. Even predators that don't eat these things directly obtain them via their prey. Fish will also alter their colour if the environment isn't quite right, so it's a good idea to review things like water quality, water chemistry, social
interactions, etc.>
He is eating frozen squid and krill and the occasional rosy red.
<Why are you feeding this fish minnows? Didn't get the memo? Just to reiterate: never, ever feed cyprinids to predatory fish. They contain too much fat and high quantities of thiaminase. Since crustaceans and at least some squid species also contain thiaminase, this is an easy way to create a vitamin B1 deficiency. Also cheap feeder fish are the #1 best way to deliver parasites into your prize fish. There is no, repeat NO, reason to use such fish. The only safe feeders are home-bred, gut-loaded killifish and livebearers, and possibly cichlids such as tilapia, assuming the predator in question can handle prey with spiny fins (not all can). Bob Fenner might well argue that you shouldn't use freshwater fish at all for marine predators, <I might. RMF> though brackish water mollies and pupfish-type killifish should be safe. <They are. RMF> The key thing is you fatten these feeders up on algae-based flake and chopped Sushi Nori, and that way you deliver a vitamin-rich mouthful to your predator. Have you ever kept cats? When cats catch birds and mice, the bits they ALWAYS eat first are the liver and guts, not the "meat". Why? Because these internal organs contain all the vitamins the cat needs to stay healthy. Muscle itself is basically empty calories, and predators don't need all that much of it. But internal organs are essential, since things like vitamin C and iodine are lacking in muscle tissue but rich in plants/algae (and therefore concentrated in the digestive tract and internal organs).>
I don't soak the food in anything since my LFS don't carry any of that stuff, and I've tried plain garlic juice but it left a nasty oily film on the top of the water.
<A real issue with predators, whether marine or freshwater, is making sure they get enough vitamins. If you can use whole lancefish for example, stuffing them with some Spirulina flake or a couple of quality pellets like Hikari Cichlid Gold will "gut load" them for you. But if you're feeding small morsels, then you really should be using a vitamin supplement.
There's an art to keeping predatory fish precisely because it's so easy to give them a vitamin-limited diet. Plenty calories, so they seem energetic, but vitamin limited, so over time they become prone to various disorders.
Neurological problems like blindness are especially common.>
When I first got him he would be clear in the mornings right when I turned the light on but so where my damsels so I didn't worry about it much. I've noticed him perching on the heater lately instead of the live rock so I thought he might be cold and the water temperature was kind of low at 75 degrees so I turned it up to 78, but he still perches there.
<You want to put a kybosh on this bad habit for a start! I'd strongly recommend moving the heater to the sump if that's an option, but failing that, use a plastic heater guard. Fish burn themselves all too easily.
Obviously, set the heater at an appropriate temperature for the species in question. The usual 25 C/77 F should be adequate. Keeping fish cooler than that really isn't sensible in the long term unless you're keeping species that particularly benefit from such conditions.>
If he see's me he will gain his color back, but lately he is still staying a little faded so that's why I writing you. Ammonia is 0 nitrites are 0 and nitrates are under 15. My only other guess is he shares a tank with a Snowflake eel which when it comes to feeding time sometimes bumps into the lion.
<Morays are "legally blind" and mostly hunt by smell. They are very opportunistic, so don't mix morays with "bite size" tankmates. Echidna spp. are primarily invertebrate eaters (hence the molariform teeth) but that doesn't mean they won't snap at any dozy fish that doesn't make at least a token effort to keep our of range. While we're talking about morays, do bear in mind they are exceedingly prone to thiaminase problems if fed just crustaceans and mussels. Do read Marco's excellent piece on the topic, here:
I thought this would stress the eel out since the lion is venomous but the eel seems unaffected. The eel resides in the live rock almost all day and its only at feeding time that he comes out.
<Echidna spp. are nocturnal and territorial, so this behaviour is entirely normal.>
By the way I feed the lion every other day or when its obvious he is hungry. He is still eating he is just almost clear in color.
<I tend to feed my predators small meals daily rather than big meals every day or two. Public aquaria work that way because it reduces aggression and predatory instincts somewhat, and in home aquaria, it helps reduce the risk
of water pollution if the predator regurgitates its meal, as they sometimes do.>
Thanks for any help you can give.
Sincerely, Colby
<My gut feeling here is that this Dendrochirus is simply too cold, but I also think a poor diet is at least part of the problem. Up the temperature to something optimal for the species you have, and vary the diet, using thiaminase-free wet-frozen foods such as strips of tilapia fillet. The use of a vitamin supplement is very important if the range of foods you're offering is limited. Only use feeder fish if you're breeding them at home and gut-loading them first. Otherwise you're simply adding another variable to the equation for no practical benefit. Do read Bob's piece on feeders and Lionfish, here:
Do note that the connection between cheap feeders and sick Lionfish is very clear. My own thoughts and solutions are here:
Hope this helps. Cheers, Neale.>

Wrasse diet...  12/20/06 <Hello, JustinN with you today> Is it ok for wrasses to eat guppies? <Feeder fish? No, I would not recommend this> And if is - is it ok for other fish - (tangs) - to eat them as well? <Tangs are herbivorous fish mostly -- I doubt they'd go after them> My wrasses sure seem to like them. <This may be so, but feeder fish are not a very good option for most any fish. Too many difficulties, too much chance for pathogen introduction, improper nutrition provision, and prepared foods are simply cheaper and more convenient.> Thank you for all your very helpful information! ML Jones <No problems, mate. Is what we're here for. Happy holidays! -JustinN>

Feeder Blockage Syndrome in Lionfish  - 11/04/06 Hello Mr. Fenner (and crew!),    <Gisho! Was in Narita just 12 hours ago!>   Long time reader of your wonderful book, the Conscientious Marine Aquarist (so much so that the pages are literally falling apart!).     This is fantastic site, and let me say "thank you" to you and all the hardworking   WWM crew for your efforts.     <Welcome>   Now to my question.  In your book, you state that the feeding of live goldfish to lionfish   contributes to feeder blockage syndrome.        Is it the particular shape or density of the goldfishes' skulls that is the cause of the blocking of the pylorus and if so, how is a goldfishes' skull any different than that of their natural saltwater prey?      <Mmm, don't exactly know what it is, but have dissected/necropsied a few lions that had apparently died with feeder goldfish impacted in their principal stomachs... Don't know if it's some chemical/physical difference in the chondros part of the minnows, or fat content...>   Or is what I surmise correct; the fact that in their natural habitat, lionfish go relatively long periods between feedings and essentially overeat when being fed too many feeder goldfish at once by well-intended aquarists? <This is definitely a factor as well>   Their digestive tracts are then not able to dissolve the skulls of the goldfish (as they are densest) and the skulls therefore essentially "pile up", and  block the gastric outlet?      <This is what I have observed... the skulls themselves "clogging" the gastric valve at the distal end of the fundus. Bob Fenner>   Or is it a combination of both? <I do think it/this syndrome is a combination of these inputs. Bob Fenner> I tried to find the answer in your book, which I was unable to, and I searched the WWM site and could not find a definitive answer.      Please advise.      Thank you so much, Gisho

Question about my sick Toadfish - PLEASE reply!  9/25/06 Good evening, <AM here now...>     I'm a college freshman with an attachment to toadfish. <Batrachoidids... neat family of animals>   I formerly lived on the east coast, where I participated in a marine science course and was introduced (quite by accident) to the species. <There are a few...>   When I moved to the mid-west for college, toadfish number one (an oyster toad) <Likely Opsanus tau> went to the Baltimore Aquarium, and on my arrival out west, I discovered a petstore that had accidentally ordered an orange toadfish.  I had missed the oyster toad greatly (despite the hell the silly little fish put me through) and decided to adopt the orange toad.     This guy was in the petstore for about a year, during which time they were giving him freshwater feeders. <An exceedingly poor practice for all involved> When I had the oyster toad, I hand-fed him pieces of squid and shrimp - occasionally a small saltwater fish (a damsel or something) but had never given him freshwater fish. <Much better>   Well, the orange toad has been a part of my life for about two and a half weeks...and I've been keeping to the same feeding regimen that the shop had him on.  As of two days ago, he started looking a little off-color, and has stopped eating.  Upon a few trips to pet stores in the area I learned that freshwater fish are very bad for saltwater fish to eat...and am rather worried about the toadfish now. <...>     I bought a couple damsels for him and put them in his tank, but he's shown no interest.  I've also bought a bag of frozen silversides for him - but he's been on live food for so long I have no idea if he'll ever warm up to the idea of a dead meal. Water stats: (If helpful) Salinity: 30, pH: 8.2 1.) Is there an all-around medication I can give him to help him recover? <Mmm, no> If so, what is it called and where can I find it? 2.) Is there anything else I can do to undo whatever damage a year's worth of freshwater PetSmart feeders has done him? <Wait, have patience, hope... may be symptomatic... some sort of fatty degeneration, a deficiency syndrome... even a physical/blockage...> 3.) Though I do have several years' saltwater fish care under my belt, any additional advice you could offer on the topic of toadfish (as it seems I'm permanently doomed to coexist with this animals!) would be most appreciated - I've noticed information on the internet is somewhat lacking. Thank you, ~ Julia    a.k.a: The crazy toadfish caretaker. <Really just a matter of time going by... and your changing to more appropriate foodstuffs if this fish spontaneously remits. Bob Fenner>

Another Solution for Finicky "Live-Only" Feeders - 05/11/06 comets and Lion fdg. f's Hi Crew, <<Howdy Ken!>> I would like to thank you for the great and vast amount of aquaria knowledge you offer to us less wizened, wet behind the ear (pun intended) keepers of the wild wet wonders. <<Quite welcome my friend...we enjoy what we do>> The following is not a question, but a suggestion for those having trouble weaning lionfish to prepared foods. <<Great!>> My Mama always taught me sharing is a two way affair. *grin* <<Indeed>> After many reading through your "feeding lionfish" FAQ's, I tried all of the prescribed methods of weaning my fuzzy dwarf off of live foods.  He was a stubborn cuss and shied away from any feeding apparatus I attempted to put in the tank.  As I am also an avid angler, the oh so obvious solution came to me in forehead slapping fashion.  What I did was to cut off the business end of a fishing hook leaving only the straight shaft, (which I dulled up) and the hooks eye.  The hook I used was large enough to supply weight to negate the currents in the tank. <<Ahh.. I see...hence the reason for not using something made of plastic/acrylic>> Attaching some light fishing line, I was ready to go, almost.  I then impaled a whole krill from head to tail down the now harmless hook and I lowered the bait into the water and let it sink to bottom.  I had enough line to stand back 6 feet from the tank as not to spook him.   It only took a few wriggling tugs across the sandbed near the fuzzy little guy before I had my first hit.  He didn't get the krill, but after a couple more twitches, lunch was served. <<Outstanding!>> I just thought I'd share this for anyone having troubles in the weaning process. I hope it works as well as it did for me. <<Thanks much for this Ken.  This sounds like an excellent solution for particularly fussy/shy feeders.  Do let us know how things progress/if the lion begins to take dead offerings without the "trickery">> Cheers, Ken <<Regards, EricR>>

White worm-like thing inside of ghost shrimp  02/12/06 Good morning... I have found a disgusting thing in my ghost shrimp tank, I was getting ready to feed my lion fish some shrimp since it is only been in the tank for a few days and the only thing that I will eat is ghost shrimp which I feed shrimp, krill and squid with some dried seaweed sheets. <... train this fish... see WWM...> I can't find any information on these worms, are they bad for my lion or any other fish to eat? <Possibly> I don't want to make my fish sick with this parasite. I cut into one of the ghost shrimp and was able to pull the worm out completely, very gross but it is a worm that is for sure. I just want to know if I can keep feeding these shrimp to my fish or if I should throw out the whole lot of them and get them from some place else. Thanks for your time. <Best to feed marines... non-marine live foods... Bob Fenner>

Accentuate The Positive, Eliminate The...Waste Products? Hi. <Hey there! Scott F. with you today!> I have a large Queen Trigger. I've been watching him for a while now. Is  it normal for him to let out waste frequently? <If he has been eating a lot, all of that digestive product has to go somewhere!> He ate 2 goldfish earlier in the day, but he lets out waste, then about 5 minutes later he'll do it again, and so on...I think its been about 4 times so far within an hour...Thank You <Well, without getting too graphic, I'd just chalk it up to his eating habits. Like people, fish eliminate wastes as they metabolize foods. These eliminations can occur at any time; fishes can run into troubles, too, being constipated, etc. By the way, do consider using foods of "marine" origin, as goldfish really do not provide a complete nutrition package for marine fishes, and may be lacking in some essential fatty acids, etc. Unless you're seeing lots of long, stringy feces (possible indication of internal parasites or other problems), or if the fish is in distress, I'd not get too worked up about the fish's elimination habits. In fact, I'd be a lot more concerned if the fish had trouble eliminating waste! Hope this helps! Regards, Scott F.>

Large FW Catfish fed feeders... I just found out you guys existed! Boy I could have used your help a long time ago. I didn't really have a question for ya, but wanted to tell you a story. I know you hear this a lot but I was also the victim of poor pet store knowledge (more than once) and ended up with a Pseudoplatystoma  corruscans (shovelnose catfish). <Cool cat, but very large with a larger mouth> The guy told me at the store that at about 6 inches the little guy was pretty much full grown. <LOL> I know now that that was completely false. Anyway we kept the little fella in our 33 gallon and he is was one of my favorites in the tank. Loved to eat and has really unique patterns. We were planning on keeping him till he got closer to a foot long. Unfortunately he never made it that far, he inherited what I think was a bacterial disease from some feeder comets, <Please, Please, PLEASE! No feeders unless your willing to QT them. Garden worms and human seafood (shrimp, mussels, etc.) is far safer for these large cats.> even though we wouldn't have had him for very long I was really mad that he died so quickly (3 months). He quit moving around and had his feelers pulled back to his side. A usually quite knowledgeable fish keeper told us to just let it ride for a couple of days, thinking he might just be shedding, <Shedding??? Catfish don't shed there skin>> since he was the only one in the tank that was sick. He died the next morning. The other fish I was misinformed about is our fire eel. He lives in the same 33 gallon tank (don't worry I've treated the tank with Pimafix because whatever the catfish had it affected our leopard leaf fish, he got some body slime and cloudy eye but everyone is healthy now) and looking at your website I found out that he may get 2-4 feet long. The pet store told me he would be max a foot and a half. Right now he is just about a foot long and happily resides under a large piece of driftwood, coming out at night and to eat out of my hand, he loves frozen shrimp!<Great, safe food. But vary it somewhat.> I was wondering how long it will take for him to get too big for the tank and have to be given away. <Not really sure.> I'll miss him but it's not fair to cage him in such a small tank. <True> Will he really get 4 feet in captivity <possible, over 3 for sure.> or could we maybe get away with keeping him in a 100 gallon or more? <Would surely allow you to keep him far longer. Min. recommended size is around 80 gallons. Upgrade your plan to a 125 or 150 and you could have him for life.> Sorry to write you a novel. Pet stores should be forced to have accurately knowledgeable staff, the losers are the poor fish and pissed off purchasers. Don't rush to write me back, Amber <Don>

Lionfish deaths resultant from goldfish feeding  Bob,  <Adam>  Two quick things. Some people in my club were talking today about the dangers of feeding goldfish to lionfish because it blocks the digestive tract. Well, I searched WWM and found lots of info on the goldfish issue, but not the info I've heard you say before about what percent of lionfish die from this and the dangers to the lion. Can you give me a good link to that? Thanks  <Don't have solid data, but I would "guess" a good percentage, perhaps 30-40 die directly or not so (fatty degeneration internally) from this practice... next in preponderance as a source of mortality, and important is "poor water quality" from this practice and being in too small volume, poor maintenance...>  Also, we would still love to have you here in SLC this year. If a fall trip would work for you, that would be great. I plan to stay in touch during these summer months, and I'll see you at IMAC.  <Will see you there, and we'll chat. Am pretty much done for 04... there are many good friends/associates here who might be willing to come out and give pitches. Would you be interested in having another of the WWM Crew make a presentation? Bob Fenner>  Thanks, Adam

Inadequacies of Feeder Goldfish - 04/03/2004  Hey,  <Hi!>  I have had my snowflake eel for about 1 month now and he loves his home, he always hides except for at night and when I feed him,  <This is typical.>  but my LFS told me to feed him small feeder goldfish or guppies.  <Yikes!>  Then I heard from someone that feeder goldfish are bad for it.  <Very true.>  Why would feeder goldfish be so bad for it?  <Well, whether this is a saltwater snowflake or one of the brackish species that uses the same common name, goldfish (or even guppies!) are very inadequate. They do not provide proper nutrients that these animals need to survive, and the eel could end up with some severe (even deadly!) nutritional deficiencies. Moreover, the use of feeder fish, unless you breed and raise them yourself, is a surefire way to introduce disease to your healthy fish.>  I mean, they eat fish and crustaceans in the wild anyway.  <True, but you won't find 'em eating goldfish - not a whole lot of oceangoing goldies out there, lol! Good food options are fresh or frozen raw shrimp, prawn, and scallops from the supermarket - same stuff you'd cook and eat yourself. Oceanic fish meat would be fine as well. If you get these meats fresh, be sure to freeze them before feeding them to your eel, as that will very significantly reduce possibilities of introducing disease. Prepared meaty foods for saltwater fish, like Ocean Nutrition's "Formula One", are excellent choices, as well.>  Please straighten this out for me, thanks. -Jeffery  <Hope to have given some clarity. Please feel free to write back if you have any further questions! Wishing you well, -Sabrina>

Live goldfish for saltwater aquaria - 3/28/04 Hey again, me and some friends where contemplating on live feeder goldfish I have a 12-13 inch snowflake eel and I feed him goldfish.
<No! Not a sustainable food. We feed our eel population human consumable prawns, anchovy, squid chopped and fed via a feeding stick. Feeder goldfish would be like feeding a toll house cookie to your five year old as an only meal. Not a long term healthy solution. Will eventually help contribute to your animal's death in my opinion, For more on feeder goldfish see here: http://www.wetwebmedia.com/goldfshfd.htm> I was wondering if they are a stable food source, and if they were healthy for it. <Absolutely not> Thanks for your time. <~Paul> Aaron

Feeder Fish (a differing opinion) I have to say, good sir, that I disagree with your evaluation of feeding live fish. <Mmm, likely you're referring to my (Bob Fenner) piece on "feeder goldfish"... not live fish, foods per se> I have a number of counter points to your argument. Firstly, the cost issue, while the apparent up front cost of the feeders may seem steep, consider the larger fish whom eat ravenously and often. You will end up spending at least a similar amount on QUALITY frozen or freeze dried foods. <Define quality> I would never feed my fish dry food in the first place, mostly because I am raising a wild fish I caught myself as fry. I also plan to set up a holding tank for ordering a large quantity (100 to 144) feeders at a time. This will decrease the cost to effectively compete with any processed food. As far as nutrition is concerned, you should realize as a biology study that it is ridiculous to say that comets or any other feeder aren't nutritious. <Not ridiculous... a statement of fact. There have been "bomb calorimetry", other certified tests of these juvenile fishes make-up.> Any wild (or tank grown) predatory fish is designed by nature or the creator (whichever you prefer) to eat other fish. <Mmm, what about predators of/on invertebrates?> That said, logic tells us that live fish would be the most nutritious food for said fish. <I beg to differ, or just differ here... do you chase down and bite/swallow live prey yourself? There are downsides to such activity... the danger of injury from prey or the chase, parasites... the time it takes to gather enough material...> And unless you've taken comets and others to a FDA lab to be processed for nutritional information, I can't believe that nutrition would be a factor. I also use a freshwater vitamin and mineral supplement to help my fish and plants, at 5 or so dollars per bottle that lasts months, I could probably feed my fish dirt and still have them be healthy and vibrant. Along with feeders, which has turned my fish's health around, I feed it insects and earthworms as well which balances out his nutritional requirements. <Good for you> I do agree that feeding live fish does increase the risk of spreading disease and/or parasites, but it comes with the territory. I has to be expected and therefore avoided by inexperienced tank owners. Anyone who has the experience and time will keep their tank clean and neat and disease free regardless of introduced agents. As for behavior modification, please tell me you're not trying to make tame goldfish out or your predatory machines. That is just sad, a predatory fish should act like a predatory fish. It should try to eat other fish and chase off (perceived) competition. <By the same token, should "predatory fishes" be granted about the same amount of space they might experience in the wild? Be exposed to predators in turn?> You can only keep a very few other species with piranhas so why would you try to keep them in a community tank? You wouldn't and neither would anyone else, so why try to keep other predatory animals together? Your statement on you web site about other countries tank keeping habits just makes you sound arrogant. Any way, I agree that colored gravel is repulsive, but a natural color (light or dark) epoxy gravel is a safe useful and quality substrate. Burping ornaments should be outlawed (grin). But substrate filtration is the most underrated filtration there is. How does a creek or a lake or the ocean filter itself? It doesn't so to speak but the "substrate" acts as a buffer and a biological cleaner. <Plus... lots of water changing...> If the undergravel filter is setup to avoid dead spots and there is enough flow to actually create a (very small) current through the gravel (which there must be a good quantity of) you almost have no need for secondary filtration. That is the setup I use and my tank requires much less maintenance as far as water changes and water polishing. I do use a hanging power filter sparingly, but it is only for the charcoal chemical filtration. Any way that is all I have to say, and you probably don't care much to hear it, but I couldn't not say anything. Oh, and this isn't meant to be mean spirited or derogatory, just my converse opinion to yours. Good day sir. Justin Harper <Thank you for proffering your points of view and rationale to support them. Bob Fenner>

Feeder Fish On The Menu? Hi, I've read the section on feeding FW feeders to SW fish (lionfish) & understand that its not good for the fishes health. <Not in the long run...> I was wondering if it was possible to breed mollies in SW & use them as feeders for the lion afterwards?  Is that the same as using FW feeders though? After all the mollies would have lived in FW before hand? <Exactly. And I think it's more of a consideration from the standpoint of overall nutrition. It may be that saltwater fish have more appropriate levels of fats and oils for marine fish than freshwater fish would. In the end, it would be better to use something like frozen silversides instead of live feeders at all, to eliminate the potential of disease transmission from the feeders, Hope this clarifies a bit. Good luck! Regards, Scott F>

Angler and "Feeder" fish I need some help!  Two weeks ago I purchased a colored angler (bright red, about 6 inches long) from the local pet store.  Everything was going great.  He was eating at least two feeder fish per day.  Yesterday when I got home, he was laying on his side, gasping and his color had faded.  Shortly there after he passed.  I took samples of my water to the pet store and they said that everything was ok.  I have a 120 gal tank with a 55 gal ecosystem for filtration and a UV sterilizer.  The other fish, small Longhorn Cow, small Lionfish, Stars and Stripes Puffer, Yellow Tang, Algae Blenny, small Banded Cat Shark, in my tank are doing fine and show no signs that anything is wrong. This is the second time I have purchased an angler with disastrous results.  What do think could be the problem? Jim <Almost undoubtedly the "feeder fish". Please see here re: http://www.wetwebmedia.com/goldfshfd.htm not nutritious, and dangerous in composition and in terms of physical blockage. Bob Fenner>

Re: new lionfish ?'s I have a 60 gallon hex set up with a small Volitans lionfish ( yes his house is going to get bigger He came with the tank) <Rad> He was eating live feeders ( aka) tuffies and Platies) I know these aren't feeder comets are they any better till I can get him off live food? <no better :-(> I've looked over the FAQ and I want this done as soon as possible.  I want him on marine foods for health reasons. I've only had him a few days but how would you go about training them to eat dead food? <starve them.> I know it can be done...I've seen it. I bought a acrylic long skinny tube ( goes in undergravels powered by air) so I could make the food move...he checks it out...does the I'm going to eat dance...and swims away? <I thought I was the only one with an I'm going to eat dance.> Now I'm going to wait a few days of no feedings...and see if hunger takes over. I bought some smelts( yeah I know but they are shiny thought they'd appeal) some shell on shrimp...any other suggestions? I've done a lot of research and this what most say to do...but sometimes there's always that person out there with a fabulous trick...I've looked into ghost shrimp and the only place with them locally is almost 2 hours away. Yes I will make the drive if need be:-)  any suggestions? <Try offering silversides, krill, shrimp, crabs, crickets... avoid oily and greasy foods.  Try freezing some of the feeders and mixing them in with the live ones.  Best Regards, Gage> Trisha

Re: pantherfish (grouper) (feeding feeders) Happy New Years, We have purchased this fish about week ago, was not eating. We starting feeding it feeding goldfish, he or she love's it. Grouper is about 4 to 5" long. How many feeding goldfish would you feed it in day. Please reply. Thank You!!!!! <None. I would train this fish on to more appropriate fare ASAP. Goldfish are not good for it. Please read here: http://www.wetwebmedia.com/goldfshfd.htm Bob Fenner>

"Killing him softly with feeders..." He or she will not seem to eat anything that is frozen but once a goldfish hits the water its gone in a second.  Which to me point that it like live food.  Since goldfish are bad what is a good substitute? (Feeder Guppy??) We have trying frozen Shrimp Brine, Marine Diet (Frozen Mixture)  Please reply with substitute and how often it should be fed. Thanks, Rob <Try frozen/defrosted meaty foods like silversides, krill..., and formulated foods made for marine fishes. This will take time, to train an animal that indeed finds, eats live foods in the wild. Bob Fenner>

Re: feeder fish article Thank you for your article on the "cons" of the use of feeder fish. It is a disgusting armchair sport. <Agreed, and eloquently put.> Even the ad on a website touting the joys of watching your fish chasing down their prey was a tribute to the sickness that the pet trade has deteriorated to in the US. I can only imagine the little goldfish, starved and shipped in the dark only to see the light for a few moments before being eaten. Today I met a person who had a killer fish, I presume piranha, that a little feeder swam up to quite innocently before being inhaled-he thought it was funny. I am also so saddened by the new 8 oz. globe holding a sad little Betta, fitted in a metal hoop and stuck in a house plant. That's supposed to be calming for humans?! <(Sigh)... sometimes hard to see progress for our species...> All I feel like doing is rescuing them all. Rita Roth St. Thomas, U.S. Virgin Islands <Ahh, was just visiting your island last month. Wish I was diving there now. Bob Fenner>

"Feeder" Goldfish Mr. Fenner, <Mr. Craddock> Good Morning. I am currently reading your book "The Conscientious Marine Aquarist" and would like to further support some of your findings in the book. Before doing this though, let me say the book is an excellent source for all aquarists. I have already preordered the new book on invertebrates due out this spring. Thanks for all of the help. <Am sure you will enjoy, gain from it as well.> A section in your book discusses the feeding of live goldfish to the tank inhabitants. There are 2 statements made that I can personally attest to. The first being that the habit of feeding some species live fish (be it gold fish, guppies or, I would assume any live fish) does tend to condition the fish to exhibit this "live food" attitude toward other tank mates not intended for consumption. Approximately 15 years ago, I had a fish only saltwater tank. It was the old style undergravel filter with crushed coral. After some trial and error and a lot of reading and talking to as many people as I could, my tank finally settled down and flourished. I considered it a small (45 gallon tall), aggressive FO tank. Once established, I had a Long Spined Porcupinefish, sometimes sold as the Porcupine Puffer (Diodon holacanthus), a Snowflake (clouded) Moray Eel (Echidna nebulosa), a Clown Trigger (Balistoides conspicillum), a Hawaiian Tang (Zebrasoma flavescens)...and a few others. The Porcupinefish, when purchased from the LFS, was being fed live fish. Once I got it home and into the tank, it wouldn't eat anything but live fish. I finally broke down and purchased some gold fish to feed it. When it ate the Goldfish, some of the gills and blood came out of the gills of the Porcupinefish since they "crush" their food against the roof of their mouth. This put the eel into a feeding frenzy. Most articles I have read, state that the Snowflake eel is a non fish-eating species. When the Porcupinefish traversed the eel's path and with the eel obviously in a excited state, the eel (I would assume their eyesight is poor) <yes> went after the Porcupinefish's small tail fin and pulled the puffer into it's lair. Needless to say, the Porcupinefish puffed up and the eel let go. After this incident, the eel would compete with the Porcupinefish for the live food. It wasn't long after this that a friend brought me a Domino Damselfish and this fish did not last more than 5 minutes. The eel would typically stay hidden until I would feed the Porcupinefish a live fish. Once the scales and fluids would move through the porcupine's gills, the eel would become very active. This was very fun to watch although the eel never went after the Porcupinefish a second time. The other statement I can attest to is the statement of converting "live fish" eaters to a non-live diet. Shortly after the period mentioned above, we had a vacation planned. We would be gone for approximately 10 days and, being in college, so would everyone else that I might have asked to feed my fish in my absence. So I resorted to an automatic feeder. Knowing the situation of my Porcupinefish and also knowing that I could not put live fish in the feeder, I crossed my fingers and hoped that the Porcupinefish would eventually get hungry enough and eat the assortment of dried foods that I had combined in the cells of the feeder. When we returned home from our vacation, I was delighted to see all of my fish healthy and from that time on, all of the fish dined voraciously on readily available, store bought, dried and/or frozen food. I can only assume that the fasting period converted the Porcupinefish. I would like to take this opportunity to thank you for your help (through your knowledge in print) and to state that your books should be a staple in any aquarists library. Thanks Again and looking forward to your next book. J.T. Craddock <Thank you for your input and kind, encouraging words. Bob Fenner>

Feeder Goldfish, fresh to marine to fresh disease transmission questions Evening WWM crew, I was talking to someone about the dangers of feeding FW feeders to SW predators and we came on kind of a tangential question. While we both agreed that feeders are a poor staple diet, how easily can a FW feeder carry diseases that could infect a SW fish? Obviously different protozoan parasites cause the more common diseases seen on FW fish versus SW fish, but what kinds of parasites, bacterial diseases, and parasitic diseases can bridge the salinity gap? <Good question... though I know of no "real scientific data, experimentation re the issue", there is seemingly endless "anecdotal evidence" that there are exceedingly few cases of disease (infectious or parasitic) in using freshwater foods for marine and vice versa... though many micro-organisms of the same or very similar species can/do make such transitions in salinity/density of waters... Especially when one considers the internal pathogens, it is surprising (to me) that there is not much (inappreciable) disease transmission. Much more to the issue in using "feeder goldfish" are fatty degeneration, gut blockage possibilities as sources of morbidity and mortality. My further take on using "feeders" as such for marine food can be found here: http://www.wetwebmedia.com/goldfshfd.htm and you'll find our correspondence in the associated FAQs file linked there... tomorrow eve. Bob Fenner> Thanks! Jay

Trigger and Puffer II Hi Bob, <Actually, this time and last time, you were "talking" to Steven Pro, one of the WWM crew members.> I realize that feeder goldfish isn't a natural food source for my Huma and trigger, however, will that somehow affect their health? <Yes, will be bad for their health. You can read more about it here http://www.wetwebmedia.com/goldfshfd.htm> I thought I was doing the right thing by feeding them live food versus frozen food. <Much easier to meet their dietary requirements with frozen foods.> I also occasionally feed them thawed mussels, shrimps, squid, and other marine variety seafood but it seemed to me that it was giving my puffer indigestion problems. Don't get me wrong, he'll eat anything, except for formula food. <Those are all good foods.> Another dumb thing that I did though was I threw in a freshwater crayfish. <Not dumb at all. Generally needed for the trigger and to a greater extent the puffer to wear down their teeth.> I'd read somewhere that it was good for the Huma to eat hard-shelled things to sharpen their teeth. My puffer ate most of the hard shell and had very bad indigestion for a couple days. I even though he was going to die cause he would float on his side! He's much better now and recovered. <A very strange occurrence, perhaps unrelated to eating the crayfish.> It seems that you're suggesting feeding them mostly frozen food as I've been doing above all the time. Anything live that I can buy occasionally that they'll like? <Ghost shrimp that have been acclimated to full strength seawater and fed a well round diet of marine origin are ok, but really not necessary.> Thanks for the reply. ~May <You are welcome. -Steven Pro>

Trigger and Puffer Hi Bob, <Steven Pro this evening.> I have a 75g tank with a 4-5 inch Huma Huma trigger, a 4-5 inch stars n stripes puffer, a clown and 2 damsels. The Huma was the last fish that I introduced in the tank. In the beginning (for the first two months or so) everything seemed fine. I'd feed my Huma and puffer 1 large feeder and they'd both share it. <By feeder, I assume you mean feeder goldfish, an absolutely horrible food for any marine fish. Please try to wean both onto foods of saltwater origin. Frozen krill, clam, mussels, and mixed "formula" foods would all be good.> In fact my puffer got lazier and didn't even bother to go for the kill anymore. He'd let the Huma chase the feeder and then would join in on the feast afterwards. I'm wondering if this is normal. Even with the feeder swimming right by him would not cause the puffer to do anything. <Maybe he realized the goldfish was bad for him (a little joke to amuse myself).> Another concern is that now my Huma is really getting mean and has started to bite my puffer whenever he approaches the dead feeder Huma is feeding on. I suppose it could be because my puffer usually takes huge bites and can swallow almost the whole feeder, leaving Huma with nothing. I don't know what to do to stop the Huma from attacking my puffer who is really shy. <Putting them in separate tanks would surely work. Also, try to feed them a little more and at different ends of the tank.> Thanks, May <Have a nice evening. -Steven Pro>

Feeder Goldfish (note: add links to subwebs) Dear WWM crew, I was just browsing (again!) the WWM site, and I found the Argument against Feeder Goldfish page ( http://www.wetwebmedia.com/goldfshfd.htm <http://www.wetwebmedia.com/goldfshfd.htm> ). I couldn't agree more. On that page, Bob wrote: "Try as I might I didn't run across any scientific work describing the chemical & physical content of "feeders". " I have long heard of thiaminase as being the primary problem with feeder golds. I know that Scott Michael is also against feeder golds, and in his book (and magazine articles in AFM) has listed the following source: Greig, R.A. and R.H. Gnaedinger. 1971. Occurrence of thiaminase in some common aquatic animals of the United States and Canada. U.S. Department of Commerce Special Scientific Report-Fisheries No. 631. I don't have access to the primary literature anymore (oh for the days when I could just go to the library on campus!), so I haven't read the journal article, but it sounds like it might be a good starting point. (I've also been unable to find this article online). I'm hoping you may have access to this article, and might be able to let us know if it supports the arguments against feeder golds...maybe you could ask Scott Michael for a copy (I'm assuming since you have some of his photos in CMA there must be some rapport) ? <Yes, we are friends and associates. I will send this note to Scotter, and thank you for your helping me and others on the "not-feeding-feeders" issue. Bob Fenner> Rich Paulhus Boston, MA PS. For some reason, the feeder gold page didn't seem to be listed site index (or at least in the sections I hunted in) but the google search worked fine. <Yikes... will check, add links. Thank you again.>

Weaning a Lion off Feeder Fish Bob, <<Actually, JasonC filling in for Bob while he is away diving.>> I have come to you before on advice and you seem to be correct, so I am here again. <<sounds good.>> I got a Red Zebra Lionfish just the other day (about 5 inches long if that), and the pet store told me that he will eat live foods, flakes, plankton, and brine shrimp. <<this is your opportunity to say, "Oh really, can I see him eat flakes?" If they say they just fed him you can do one of two things - don't believe them OR say, "Cool, what time do you feed, and I'll come back tomorrow and watch." If they avoid your questions, well then you know the answer...>> I have put frozen brine shrimp in, and plankton, I have not seen him eat it for the most part with the exception of 1 or 2 bites.  I have read that if he is being weaned off live fish, this can happen and when he gets hungry he will eat. <<true>> Can this fish be weaned off live stuff if that is what he was eating, or does this pet store not know what they are talking about? <<you can wean them off live, and you should wean them off live foods, but it will most likely take some time and patience.>> Or should I just give it time and when he gets hungry will he eat the frozen plankton floating around the tank? <<He's going to need more than plankton - these are meat eaters... you need to try some silversides and whole krill. I'd think these would get better results that brine shrimp or flakes. Do you think if we were talking about a regular lion [you know, the big cat] that we could get it excited about a bowl of corn-flakes? Probably not, but a bucket of chicken... that's another story.>> Joe <<Good luck, and do stay the course and get that lion eating something besides live feeder fish - you'll get to enjoy it for a long, long time. Cheers, J -- >>

Curious about feeding Dear Mr. Fenner: <You got Steven Pro today.> I have a 125 gallon tank with a medium sized vol lionfish. I added a brown-banded bamboo sharked freshly hatched from an egg. I know that I shouldn't try to feed him for about 2-2.5 weeks but I am wondering whether live food or frozen food would be the best starter selection? <I would slowly acclimate ghost shrimp to full strength seawater and allow the shark to eat whenever he wishes.> The lionfish only eats live food, especially ghost shrimp. Is there any way to wean him off of live food and help him adapt to frozen? <Yes, but is going to be harder than normal because I think you should provide a constantly available food source for the shark initially. After the shark is eating well, keep the ghost shrimp separate. Then scoop them up in a net and put the net in the tank and allow the shrimp to scurry out of the net. Soon the Lionfish will associate the net with food and will approach the net as soon as it goes in the tank. Eventually, feeding directly out of the net. When that occurs, try putting something else in their like defrosted, frozen krill. Soon, he will eat anything that is in the net.> These are the only 2 fish I plan to keep in the tank and how do you feel about their compatibility? <There should be enough room for just the two of them.> Any advice will be greatly appreciated. Thanks so much for your time and patience in this matter. Sincerely, Matthew <You are welcome. -Steven Pro>

Tiger Shovelnose Mr. Fenner, We have a large Tiger Shovelnose whose belly has been swollen for about a week now. We only feed him goldfish, but were afraid that he may have swallowed some rocks in his frenzy.  <Maybe... more likely the goldfish themselves. Please read the following: http://wetwebmedia.com/goldfshfd.htm> What could it be and what can we do? Thank you for your help, Christine and Tony <Not much... the trauma of handling this Pimelodid catfish at this point is likely worse than just waiting, hoping. If the animal were small (let's say a foot or so in length) it might be advisable to give it a bath in Epsom salts and tank water (not in the main tank) or even administer vegetable oil down its buccal cavity (past the constriction to the rear) with a plastic pipette... Have seen these problems resolve w/o intervention many times before. Let's hope this one does as well. Do look into other foods. Bob Fenner>

a question about feeders  Hello!  I am using feeder fish in an experiment I'm doing for my Botany class. I am gathering information to write a little bit of background info for my report. Can you tell me the genus and species name of comet feeder fish? Thank you,  Anna  <Carassius auratus... though some folks think this is a hybrid: C. auratus X C. goeblio. Bob Fenner, www.WetWebMedia.com>

Question about Feeder Fish I keep several marine fish, and occasionally I do feed them a molly or a guppy. Now, I know that feeder goldfish can cause "gut problems" but is this also true for mollies and guppies? <Not nearly as much... due to size and make-up (feeder goldfish are very fatty... and cartilaginous/hard to digest). If fed occasionally, should be no problem. Bob Fenner>

Lionfish (feeding, not) Bob it has been 8 days now and the lion still refuses to eat krill.  Anotherwards he hasn't ate at all. I've tried silversides and he doesn't show to be interested. I've check out your web page on feeding lions feeders and I didn't find any info on how to get a lion off feeder fish. Bob what should I do with this lionfish? Maybe you could give me the exact address to the info on how to take a lion off feeders. Thank you please respond soon. <This may be a specimen that just won't be weaned off of live food, sad to say/state. If it were mine, I would offer live foods (even freshwater) for the meanwhile, and resume "shaking" dead/defrosted material on a "stick" when it is in fuller condition> Will copper kill lesions off parrot fish?  <Much more likely to kill the fish instead... Do consider "taking both these specimens back" to your dealer if you can. Bob Fenner>

Feeders I read your argument on feeder comets, I agree. I really don't think that the goldfish are a healthy source of energy. I do however think that shrimp are a good source of food for my lion. however you would be able to easily disprove me, am have no biology other than from my high school years. I just do physics. anyways I got about eight ghost shrimp today and I will feed my lion a peppermint or camelback shrimp every week or so. I don't overfeed and I keep the feeder shrimp healthy and well fed with a diverse diet. I indirectly feed my lion his veggies through the feeders. what do you think about that? he seems to be getting a little more aggressive and I have only gotten him to eat some thawed krill once. the ghost shrimp don't look any better than the comets but am hoping that the shells of the shrimp offer compounds not normally found in dry foods or comets. let me know if am wrong. thanks Jon Trowbridge <Sounds like a good game plan... and no worries with those shrimp shells... Lions even eat Hermit crabs w/o problems. Bob F. who used to teach H.S. Physics>

Feeding Lions, feeders I have a medium sized lionfish and I was told that it is not healthy to feed him goldfish because it is not nutritious. So far, I'm having A LOT of trouble feeding the lionfish frozen krill. Now, I'm feeding him a combination of a goldfish or ghost shrimp every other day. My question is twofold: 1. Is this combination of shrimp or goldfish fed every other day still dangerous for the lionfish? <Possibly... I'd at least feed less frequently... easy to kill these fishes with overfeeding... And do try some other "frozen/defrosted" fish food species like silversides, or cut fish you can buy for human consumption or bait...> 2. I was theorizing feeding the goldfish more nutritious food, maybe Spirulina rather than regular goldfish flakes; this in turn would make nutritious goldfish for the lionfish. Does this theory have any validity, or is this a mass collection of stupidity? <No to supplementing the feeder's diets in attempt to make them more suitable... problems lie in structure, make up and digestibility... that can't be solved this way.> A prompt response would be greatly appreciated. Mark <Bob Fenner, who apologizes for the late response, been traveling... pls read the feeding feeders article stored on the wetwebmedia.com site for more> 

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