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Spotty tiger Oscar and other problems    9/27/14
Hi there my husband has 3 freshwater tropical aquariums, one of them has an albino Oscar, a tiger Oscar, a Kissing Gourami, a Firemouth cichlid, a Nicaraguan, and two Plecos. The albino Oscar has lost some scales on a large area on both side looking almost like flesh wounds and the tiger Oscar has a few small/large white greyish spots on one side.
<Do look at the behaviour/s of the Plec and the Kissing Gourami. Plecs are sometimes seen to attach onto Oscars and other large fish, rasping away at the mucous. Similarly, Kissing Gouramis very occasionally do this too. In both cases the problem seems to be triggered by hunger. Plecs have huge appetites and need a lot of food, particularly "filling" greens (such as lettuce, courgette and sweet potato) pretty much on offer every day of the week. Without these foods, they feel hungry even if they're getting some pellets or wafers, kind of like how people feel hungry even if they've actually eaten quite a lot of protein and fat (e.g., meat) but very little fibre (i.e., fresh fruit and vegetables). So, review what your Plecs are being offered. Perhaps move them away from the Oscars for a few weeks, medicate as per Finrot, optimise water quality (zero ammonia and nitrite, minimal nitrate) and see what happens. Kissing Gouramis are a species prone to starvation in aquaria. They're filter feeders in the wild, and need very large quantities of food to do well. That's one reason they're often tricky to keep, and even those that do survive have a concave profile to their bodies that shows they're underweight. A decent portion of finely powdered Spirulina flake offered 3-4 times a day will help a lot, alongside the odd algae wafer, frozen brine shrimp, live daphnia, etc.>
And in the second, he has a few Plecos, and some other communal fish, of which the biggest Pleco has a few grey patches but the third all fish seem fine, please could u help me with this as I really have no clue, well to be honest I have a couple but I'm not am expert so not really sure many thanks sheen
<If the Plec has some problems with its body as well, I would suspect water quality. Review and act accordingly. To recap, any tank with an Oscar or a Plec (or both!) needs to be big, minimum 55 gallons for one, 75 gallons for both, and equipped with a large filter. By large, I mean choose a filter from your favourite range that's for the aquarium the next size up; so if you have a 75 gallon tank, choose a filter rated for tanks 100 gallons or more. Make sense? Do also read:
Cheers, Neale.>

HELLPPPP!!!    7/24/13
My poor Oscar suddenly  was being bullied in the tank that we have for them.  I removed him and put him in his own tank alone.  However, he is barely hanging on.  Is there any medicine or anything I can do to help my poor little Oscar. its apparent to me that in the few hours they were alone together he was really beat on his fins are bitten and he just looks awful.  Please tell me how I can nurse this poor guy back to be healthy.
Thanks Heather
<I would leave the lights off... and possibly treat with Maracyn I and II in combination; safe, effective. Bob Fenner>

Tiger Oscar attack (Bob, Oscar damage or Catfish damage?)<<Likely the latter>> 9/3/10
I have had 2 Tiger Oscars in a 125 gallon tank for over a year with a 14 inch Pleco .
They have always gotten along well, as well as can be expected.
<Indeed! Oscars are not famously sociable except as mated pairs.>
The Oscars are easily 15 inches and 12 inches. I clean their tank every 3rd week, draining close to 75% of the water each time. I also use this time to "rearrange" the decor in the tank, to keep them entertained.
<Likely helps to break up territories a bit, which is good, because it prevents any one specimen become super-dominant. That's the theory, anyway.>
They are fed flake/frozen food daily, and they get about 25 feeders every Tuesday to chase around.
<No, don't feed them feeder fish! It's VERY VERY VERY bad for them. Gosh, I have no idea why shops still sell these "parasite bombs". Let's put the cruelty aspect aside (and it is cruel). In terms of nutrition, Goldfish and Minnows suck. They contain a lot of fat and something called Thiaminase that breaks down Vitamin B1. There is AMPLE laboratory and real world evidence that Thiaminase causes predatory animals including fish all kinds of health problems, from reproductive issues through to poor immune responses and deterioration of the nervous system. The use of feeder fish also increases aggression for reasons not altogether understood. There are absolutely NO good reasons to use feeder fish, and lots of reasons not to.
Thankfully you can't buy them here in England so it's mostly a non-issue, but the US pet trade still sells them, creating all sorts of problems for American aquarists. Want to give your Oscar something it would eat in the wild? See those massive jaws, they're for crushing things! So try snails or crayfish or whole shrimp. They love earthworms!>
It keeps them from fighting with each other.
<No it doesn't. For some reason it actually makes them more scrappy.>
Last week, I did not stop to buy them feeders. They were fighting by Thursday, and by Saturday morning the smaller Oscar was laying on the bottom of the tank, covered in white "fuzz" spots, and there is a side of their tank without gravel where you could see the scales on the bottom.
<I don't think this had anything to do with you not buying feeder fish.
Indeed, it's more likely that buy using feeder fish you've increased their tendency towards aggression, and this week it might have spilled over into outright violence. That said, by the look of the damage, I think the Pleco is to blame here. Oscars fight by wrestling, and usually you find damage to the jaws, face and fins as they bite at each other. This looks like someone scraped away at the flanks. It's possible one Oscar damaged the other, and the scent of blood was enough to get your Pleco hungry. Within the confines of your aquarium the stressed or otherwise weakened Oscar was an easy target.>
My wife thought she was dead. When I got home from work, I grabbed a net and was going to remove her from the tank, but as soon as the net hit the water she moved. I moved some plants and decor in the tank so she has her own little "cove" where she can be sheltered from the other Oscar completely and not have to worry about defending herself. She still shows an appetite at feeding time, and will swim around on occasion, usually after lights are out. What is the best  medication to use, anti-fungal as a preventative, stress coat, or Melafix?
<Obviously needs excellent water quality and its own tank. I'd treat with an antibiotic given the scale of the damage; blood poisoning or Finrot-type infections are very probable otherwise. Melafix is largely useless, and this damage goes beyond what Stress Coat can do alone, though using it alongside antibiotics would be a good idea.>
And how long will it take for the scales to regrow?
<This will take months to heal.>
Any other advice would be greatly appreciated.
<Please do stop with the feeders. Ethics aside, they're just D-U-M-B dumb.
If you must use live fish for some obligate piscivore -- which your Oscar isn't -- you have to breed your own livebearers or killifish at home, as these lack Thiaminase and have less fat. Cyprinids such as minnows and Goldfish aren't an option.>
Thank you, Eric
<Glad to help. Cheers, Neale.>

Oscar's tail (entire tail) eaten off, help!  5-10-09
I'm in a bit of a hurry (as I'm sure you'll understand why, as you read on), so I apologize in advance if this information is already posted on your site.
<Likely is written elsewhere, and you would actually get a reply more rapidly using the Search box...>
Our Oscar and Pacu have been tankmates since they were babies, together for over a year now. They'd been best buddies, with only the occasional bullying by the Pacu. Well, it finally happened, 2 nights ago we caught the Pacu eating the Oscar.
<Pacu are omnivores with a taste for fruit, but I'm sure they'll bite small, sick, weak or moribund fish. So while they're fairly trustworthy fish kept alongside tankmates of similar size, if this Oscar was substantially smaller than the Pacu, or for some reason weakened, then that might explain what's happened here.>
Fins are nearly completely gone, tail IS entirely eaten away (into the fleshy part). I'm going to attach a photo. Naturally, we moved it into a QT tank, doing water changes daily. Didn't think Oscar was going to even make it through that first hour, now here we are, 2 days later and he's figured out how to swim normally again, ate last night, poo'd just fine! My main question (and reason for writing) is...will adding aquarium salt reduce the risk of infection/fungus?
Will it also aid in the healing process?
I intend to add some tonight, just because I know that it does help, I'm just not sure how, haha.
<The idea salt is a cure-all is an old one, but it really isn't much good.
For one thing, marine fish get bacterial infections, and they're in seawater! This Oscar is in seriously bad shape. You need a robust, aggressive treatment here that deals with both Fungal and Bacterial infections, since your Oscar WILL get both if not promptly treated. I'd be looking at Seachem PolyGuard, Seachem NeoPlex, eSHa 2000 or similar.
Obviously NOT something like Melafix, which is, at best, a preventative tonic. A proper antibiotic such as Maracyn would be a very sensible augment to the treatment, especially if the tissue remained red and sore for more than a week or so.>
Will the tail grow back, or will our little Oscar just be tail-less for the rest of it's life (if it continues to survive and do well)?
<Given time, fish show an amazing ability to regenerate fins. It all depends how much of the bone on tip of the caudal peduncle (the muscular "stem" of the tail) has been damaged. If the peduncle is basically sound
and the bones intact, with luck, this fish could regrow its fins.>
Thank you in advance for ANY information you can give me. It's MUCH appreciated.
<Cheers, Neale.>

Re: Oscar's tail (entire tail) eaten off, help!  5-10-09
"Pacu are omnivores with a taste for fruit, but I'm sure they'll bite small, sick, weak or moribund fish. So while they're fairly trustworthy fish kept alongside tankmates of similar size, if this Oscar was substantially smaller than the Pacu, or for some reason weakened, then that might explain what's happened here."
Not this little bastard, I've learned there's nothing trustworthy about him! :) While the fish is incredibly loving and docile with me (insists upon being pet during water changes and such), it will eat anything in the tank simply because it can catch it.
<Ah, I see. Does happen, as I said. The idea Pacu are pure herbivores is widely quoted by erroneous; do also be careful when petting your Pacu: they are confirmed "biters" and have extremely strong teeth and jaws evolved for crushing nuts. Your fingertips will be as nothing in comparison!>
Tis a naughty little fishie. I really should have known better, however since the O is just over half the size of Pacu and they'd been together so long, I made the simple mistake of believing they were fine together.
Lesson learned.
<The hard way...>
I'm not sure why it prefers "meat" over "fruit", maybe because it's THE DEVIL??
<They're omnivores, as I said, and view both as food, much as we do. While Pacu are generally very good choices for robust communities alongside Red-tail Catfish and the like, clearly combining them with smaller Oscars isn't reliable.>
Also, we will treat the Oscar, I can't tell you how much we appreciate the advice on medication. While the Oscar is in bad shape, I'm quite surprised at how much fight this little thing has in it! Maybe it's because my 5 year old sits at the QT tank all day chanting "Fight, fight, fight". Hehe :)
<Hmm... is she chanting for a rematch, or simply hoping the Oscar lives to fight another day?>
I'll be bookmarking this site, I'm very happy with the quick response and such detailed, helpful information. You're amazing :)
<Thanks for the kind words. Cheers, Neale.>

Re: Oscar's tail (entire tail) eaten off, help!  5/16/09
Hiya Neale...Just an update on my Oscar, in case you remember the conversation we had about it! "Dogfish" is doing very well, appears to have some re-growth of the fins, still not sure whether or not the tail will come back. It is eating well, swimming wonderfully, and is getting excited to see me at the tank again :) Yay! Strong little fishie, eh?
<Glad to hear the good news. Clearly you're doing the right things, and let's hope for a complete recovery! Cheers, Neale.>  

Oscar hurt 2/18/10
I have 2 Oscars, 1 is approx 7" (tiger) the other quite small approx. 2" (albino tiger). Also, in the tank is a 10" irr. shark ,a black knife, a green Severum, and a 8" Pleco. Tonight when I got home it appeared that the big Oscar tried to eat the small one. This happened once before but awhile ago.
<And of course you sensibly moved the smaller fish to its own aquarium...
only a fool would leave them together after something like this, surely?>
Now his scales are all messed up and he swims upside down and in spirals.
<Ah, but no, you *did* leave them together.>
Is the anything I can do or is he injured beyond help?
<Obviously each Oscar needs its own aquarium. Sexually mature specimens are not tolerant of one another, except in very large aquaria. Since you don't mention the size of the aquarium, I'm going to assume it's something far too small, like a 55 gallon system. A single Oscar, by itself, will take over a 55 gallon tank. At 75-90 gallons, you could add ONE catfish. But for the selection of fish you have, anything under 200 gallons would be insane.>
I did put StressCoat in the tank and separated him into one of my breeder net cages, Please help .
<Breeder cages? You mean you have Oscars cooped up in those things for Guppy fry? How's that going to help? Move these fish to their own aquaria, and treat as per Finrot. Given proper water quality and a tank of its own, an injured Oscar should get better, and the loss of a few scales shouldn't be fatal. Does rather depend on whether you're prepared to make the effort.
Unfortunately we get messages from too many aquarists who can't be bothered, and simply euthanise fish they've somehow managed to get half-killed anyway. Sad I know, but it's the reality, and if you detect my slightly cross tone here, forgive me, but that's the reason. Cheers, Neale.>
re: Oscar hurt
Look I didn't ask for help to be berated like that.
<Well, if I hurt your feelings, I'm sorry.>
I have kept fish of all species for over 25 years and never ran into this problem before.
<Perhaps, but it wasn't a surprising problem. Oscars don't get along.>
As far as the tank goes its a 125 gallon with FX5 Filter turning the water over 3x per hour.
<Way too little water circulation. For large cichlids, you really should have much higher turnover rates, at least 6 times per hour, and ideally 8 or more.>
Not a 55 Gallon like you think.
<Still, it's too small for the Oscars, or they wouldn't be fighting. What can I say?>
I put him in that to separate him immediately with no where else to put him, sorry I don't have another tank but I do the best I can.
<Sometimes the best you can do isn't good enough.>
I guess that why I don't go to these sites. Who needs to be setup for a lashing when they ask for help.
<All I can say is that I analyzed your problem on the data offered, and gave you what is an accurate diagnosis. I'm not sure what else you expected me to say. You didn't tell me the size of the tank. Since most of the "my Oscar killed its tankmate" messages come from people with small tanks, I mentioned how a small tank wouldn't work.>
I have NEVER euthanised a fish.
<Sometimes euthanasia is appropriate, so in itself isn't a black mark against anyone. What matters is how you euthanise a fish, and that you perform euthanasia when it's appropriate to do so.>
I do put forth effort.
<Glad to hear it.>
This Oscar has been with other Oscars and never hurt the smaller like this.
<When they're younger, they're tolerant. But once sexually mature, they become aggressive.>
Sorry for the inconvenience, CHEERS, Jeff
<No inconvenience at all. I'm merely trying to help. Cheers, Neale.>
re: Oscar hurt
I was wrong it is filtered 6x per hour.
<Well, that's much better.>
So basically no more fish for that tank especially another Oscar.
<Depends on the fish you're adding. A good approach with these robust communities, what in England we often call rough-and-tumble communities, is to choose fish that are completely different from each other. That way,
no-one sees anyone else as a threat. So an Oscar, a Plec, a trio of Tinfoil Barbs, perhaps a Leporinus (though these can be nasty) and maybe some type of "eel" like a Fire Eel can work out great. All the fish are looking for
different things out of life, so no-one gets too cranky. But keep a bunch of cichlids together, and inevitably they *all* want the same flowerpot or cave, and the end result is a fight. If the tank is overstocked, then aggression might be minimised because no-one becomes the territory holder, but overstocked tanks create a whole set of new problems, like high nitrate levels and the resulting likelihood of sicknesses such as Hexamita infections.>
I guess that I just got a very territorial one because I did have 3 together for 6 years until my heater unknowingly broke and they got sick.
<Sounds a fair analysis. If you had three females for example, then you'd be fine. But males are mutually aggressive, and mated pairs will also be aggressive to any other Oscars. In general, Oscars are best kept one to a tank. That way, they're very peaceful by big cichlid standards.>
I have since prevented that from happening again by getting an alarm that is audible as well as visual if it wavers more than 3 degrees.
<Would further recommend a "heater guard" if they sell them for the heater you have. These are simply plastic clip-on things that keep the heater safe. Better still, get an out-of-tank heater like the Hydor ETH, or else build a sump and stick the heater in there.>
Thanks Sorry about the confusion, Jeff
<No problems. Good luck, Neale.>

Oscar Issues hlth.  - 06/08/2007
One of my Oscars has recurrent white circles that come and go, mainly on his head. They typically clear up with water changes, but this time nothing has helped. The tank is a 115 gallon.
Today I added a little aquarium salt and have made the water more alkaline, but it's too soon to know if it will help. The pic I've included is a little large, but it's hard to photograph the circles. I'm guessing it's a fungus and maybe this Oscar has a poor immune system because all the other fish in the aquarium seem to be fine. He has had a deformed head since birth, but he's about 10" now and hasn't had any other problems.
I am reluctant to medicate because I don't want to compromise the biological filter. Any suggestions?
<Steve, although I'm not 100% sure (the photo is a bit blurry) my immediate feeling is that these are bite marks. Since you have more than one Oscar in the tank, it's likely they're fighting. Bit marks typically consist not of a single ring, but rather a pattern of tiny scratches (the teeth marks) arranged in a circle. If no serious harm is done, you may as well leave them to it. Medication shouldn't harm the biological filter if used as directed on the packaging. In this case, an anti-Finrot remedy might be in order, just to make sure nothing serious developed. Salt is neither here nor there really, and won't stop a bacterial infection though it may help against fungus. I personally wouldn't bother with salt, and instead would use a proper antibacterial of some kind. Given the fish is otherwise healthy, and these wounds shouldn't have damaged the skin too badly, even something as lightweight as Melafix might have a role. Cheers, Neale.>

One of my Oscars is ill... terr.   - 02/21/07
We have a albino Oscar and two red tiger Oscars in a 75 gallon tank together. The 2 red tiger Oscars we have had for about 2 years now. They were bought together, and are always hanging out together. I believe they have been trying to mate for some time, but never lay eggs.
<Mmm, might be that they're both male...>
Recently though, the female red Oscar's skin on her head has been peeling off and leaving a pinkish, fleshy look to it. Also she lays on the bottom of the tank a lot, and has not had the greatest appetite. Just about every time one of the other Oscars gets near her she shakes her back fin at them (almost looks like it's vibrating).
<This is a good clue... these fish are engaged in fighting... the one is losing...>
She will do this even when she is laying almost sideways on the bottom of the tank. She does venture to the top sometimes, and will eat sometimes also. Do you have any suggestions as to what might be causing this?
<Territoriality in a word>
And any treatments you suggest. I am afraid she is going to die is this continues.
Thank you for your time,
Kelley Murry
<Mmm, well, you're faced with basically two choices... to separate these two fish or to try "something else" to "take their minds off each other".... Like adding "ditherfish"... I would at least put a separator twixt them... Now. You can read re ditherfish on WWM, elsewhere. Bob Fenner>

Oscar gill 10/16/05
Hey crew,
I have a Tiger Oscar- 7"- that I believe may have gotten into a fight. This is because one of his/her gills looks out of place. I don't know how to help my Oscar... What should I do?
<Mmm, keep water quality optimized, stable, provide good nutrition... in short, just good upkeep... not much can be done with such injuries... they either heal on their own or leave the fish with a deformity. Bob Fenner>

Beat Up Oscar
Hello, My name is Josef Moran and I have a question about my  Oscar.  He is a red Oscar and he is getting bullied by my other two Oscars.  They are albino .
When this happens he floats there like he is dead. And I  was wondering if you can tell me if there is any thing I can do to help my red  Oscar.
< The other two Oscars may be breeding. The pair will guard the eggs and fry from all other fish. they will even kill the other fish if they are too close. I think the best thing to do is remove the beat up Oscar before he is killed.-Chuck>

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