About Christy Expertise I can answer some questions regarding freshwater fish ranging from their care to diagnosing common diseases or problems with the fish. I can also answer questions regarding the care and maintenance of an aquarium. I haven't had much luck with live plants, so can't help in that area very much. Not real good with explaining salt water or brackish set ups too well either. Also regarding goldfish, I have some comets, and have a little experience with them but mostly just general info on them. I AM NOT THAT FAMILIAR WITH ANY OF THE FANCY VARIETIES OF GOLDFISH. YOU MIGHT BE BETTER DIRECTING THOSE QUERIES TO AN EXPERT MORE FAMILIAR WITH THEM. If I can't answer or don't know something, I'll let you know, so don't be upset if I reject your question, I'll always explain why. I would just rather not answer then give an answer I'm not confident about.
Experience All personal, first hand, general fishkeeping experience. I've had fresh water aquariums now for about 7 years. I've had tropical/community fish tanks, African cichlids, South American cichlids, brackish water puffer fish, and a lot of other varieties in between.
Education/Credentials None, all personal experience
Question We have had our oscar for approx. 9 months, and he has grown quite large. Three days ago, I fed him some feeder fish and now he is starting to film over and laying on his side. The rainbow shark and the plecostamus seem to be doing fine. Any suggestions?
Answer Hi Theresa
What size is this tank? For the fish you have, you should ideally have them in at least a 60-75+ gallon tank. It almost sounds like a water quality issue. But, since you're using feeders, not really sure. So first I would suggest picking up a good test kit, preferably the liquid dropper kind. Make sure ammonia and nitrite levels are reading 0 ppm, nitrate levels under 20 ppm. Also make sure the ph is staying stable. That way you can rule out water quality as the cause. Some fish may react poorly more so then other fish. Oscars are probably a bit more heartier, but if he's stressed or not altogether well, he will be more susceptible to water quality issues.
Feeder fish are not a good thing to feed fish. Feeders from the store are known to be full of diseases and parasites. I just bought a couple of feeder comet goldfish for my pond. They all looked so sickly and awful, but I was planning on quaranting them for a few weeks and doing a round of antiparasite/antibacterial meds anyway before adding them to my pond. The lady at the store told me how she had fished out over 50 dead fish from the feeder tank the night before. Because they're just "feeder fish" they aren't kept in the most ideal conditions. For those that insist on using feeders, it's best to breed your own. But even then, it shouldn't be the main diet for fish, they should have a varied diet so they get all their vitamins and minerals.
If the water quality checks out ok, then I would say you're dealing with something brought in from the feeder. Film on the skin is excess slime coating. Fish will excrete excess slime coat when their skin is being irritaed-like with poor water quality, or also parasite infections can cause this. There's also a bacterial infection that can cause symptoms similar to that. Like I said, first rule out the water quality as an issue. Then, I would quarantine the fish to a separate tank if you can, since most parasite medications are toxic to those other 2 fish in the tank. I would add 1 tablespoon of aquarium salt per 5 US gallons to start. Again, those other fish are going to be sensitive to salt as well. Then a round of Quick Cure or some med that contains formalin or malachite green should help with most parasite infections. Just follow the directions on the label.
Let me know if that doesn't help, or if other symptoms develop. Good luck!
