Red Tiger Oscar

Question
QUESTION: Hi David I have a few questions about my red tiger Oscar. My Oscar has been turning light grey and he is not as black as he was when I bought him.I don't know if this is normal or if he is sick.I have also noticed that he has been leaning sideways.What does this mean? My last question is what is the best thing to feed him? I have been feeding pieces of krill and I buy small goldfish and feeder guppies for my large mouth bass and I don't know if it is ok for him to be eating that.Please get back to me as soon as you can. Thank you

ANSWER: Hi Jose:  Fish can turn colors for many reason and one of those reason is disease. Another reason can be because of a change in diet.  Is your tank heated??? if so what is the temperature????   Krill is good for fish but I would try to feed him the smaller variety whole.  I am not a fan of pellets but you can try to feed him pellets one day and Krill the next.... I would not feed him feeder fish because of the risk on introducing illness into your tank.  There is not a lot of food value in feeder fish so the risk is just not worth it.  Feeder fish are not cared for very well and often times are sick.  keep me posted... dave

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QUESTION: Hi it's Jose again. thank you for the answer. So about my tank. Well I wouldn't say it's heated but I have a background wallpaper on the back side of the tank with a neon light behind it that gives light and a little bit of heat. I will defiantly get some pellets and mix his diet. One more thing is that I just recently had one of my fish die and I don't exactly remember what kind it was but it was black with huge eyes and a big tail. anywase He had lost a lot of scales and it looked like he also lost some weight but he had been eating fine. I don't know if my largemouth bass had attacked him or even my Oscar. After that I noticed him float up to the surface and try to swim down and then float back up. The same process would happen over and over again until he just never swam back down. Could this have been caused by disease or something else. Please get back to me ASAP. Thank you... Jose

Answer
Hi Jose:  Tropical fish must be kept in a heated tank. The ideal temperature for tropical fish is 78-82 degrees.  In lower temperatures they can not fight off diseases such as fungus, ICH, and other parasitical infestations. They are also lethargic and eventually die.  You need a heater in your tank.  It would be pointless to try to medicate your fish at this point because I have a feeling that 90% of what you have described is due to lack of warm water.  dave