I have a black (maybe dalmation?) molly who has been through at least 2 rounds of illness recently. I have had her for about a year and a half. She was living in a 55 gallon planted freshwater tank with a CO2 system (temp 78, ph 7.0, nit/nitrate/ammonia 0, hardness 300) with 1 pictus cat, 1 tiger barb, and 3 rosy barbs as tank mates. I started out with 3 mollies, but only one lived past about 6 months. I added 2 blue gouramis about 3 months ago. Not too long after that the black molly developed a case of Ick. I removed her to a 20 gallon tank for treatment. No other fish in the 55 gallon showed signs of Ick, but I treated the tank once anyway, since I'd seen it on one fish. I used API brand "Liquid Super Ick Cure".
Initially, I used water from the 55 gallon tank to set up the 20 gallon in order to avoid changing the water conditions too suddenly. The ph in the 20 gallon tank (this tank is about 1 month old) is now 7.8, and the temp is 80 degrees. I had the water tested at a pet store yesterday, and ammonia/nitrite and nitrate are at 0, water hardness is 300. I don't know the brand of the test kit they used. I have been adding Instant Ocean salt to this tank slowly. It is now at about 2 tablespoons of slat per gallon. So far, it is still too low for the hydrometer I have to measure. I treated the molly for Ick with the same API brand liquid Ick Cure. The molly's Ick cleared up, but she then showed signs of fin and tail rot. I did two days of partial water changes and continued increasing the salt slowly. Then I treated for 7 days with API Melafix (anti-bacterial). Her fins and tail have recovered and grown back properly, although are clear in the area where they had been damaged.
At this point she had considerable silvery areas on her body, in addition to rusty colored mottling. I did 2 more water changes and then treated for 7 days with API Pimafix (anti-fungal). During this time I have only had a corner box filter running to avoid removing medication from the water. I am adding a AquaClear hang on tank (50 gallon rating) filter today. The Pimafix did not change the strange coloration she is exhibiting.
I took pictures and asked around at 3 different stores (as well as having the water tested multiple times) and no one could tell me what, if anything, was wrong with my fish. Everyone seemed to believe it was simply a pigmentation change. I could believe this (the fish is eating, and swimming normally. Her fins and posture are also normal) if it weren't for the fact that it looks like some of the rusty orange stuff is over the top of one cornea. Also, her skin surface does not seem smooth to me as it should be.
I am including 2 of the photos I took in the hopes that some one might have seen something like this before. My plan is to keep the molly permanently in the smaller tank and I would like to get her a couple of companion mollies. However, I do not want to do that until I am sure she is well!
A final note: Until about 3 weeks ago this fish was solid black.
Any ideas would be much appreciated!!