cyst on fish ????

[dogsby8]

55 gal
15 angels
3 platys
3 moons
4 cories
2 clown loaches
2 botia loaches
1 male beta

about a month ago had algea bloom and did a 25 gal water change. on the same day noticed what looked like a cyst on an angel. two days later a big wound then white tissue hanging out of it. angel eating fine. used melafix. angel stoped eating next day and died. every thing seemed fine for a week, then noticed another cyst on another angel. used mels fix again didnt help. water para were good before but now nitrites unsafe. did a 25 gal water change.water para now good. went to pet store a got maracyn. treated tank as directed on package. that angel is now getting scales back . but 3 other angels and betta now have large white cysts on them . what can i do to stop this cycle.no new fish have been introduced since oct. feeding same flake food, brine shrimp and blood worms. temp at 78. ph 7.2,0 nitrates, 0 nitrites.

[Allivymar]

Sounds like you have a case of columnaris running rampant in your tank. I'm sorry to say I'm not surprised; your tank is really overstocked. Angels alone need around 10g each. The stress of all those fish, the strain on the filtration and what sounds like infrequent water changes are likely reducing the immune system of the fish and leaving them open to disease.

I strongly suggest upping your water change frequency; at least once a week if not twice (around 20-30%); also, what are the ammonia levels? I also suggest looking into another large tank; if thats impossible, you may want to look into returning some of the angelfish or giving them away/selling them.

Lastly, I recommend reading the following article. It give great advice on what columnaris is: http://www.aquamaniacs.net/flex.html . The only thing I'd add to it, is if the fish aren't eating, use Kanacyn, If they are definitely get medicated food; you can find some here: http://www.flguppiesplus.com/_wsn/page3.html

[dogsby8]

ammonia levels at o. test water daily and change as needed. will be moving fish in two months i hope to a 120 gal or larger tank , have to build the room first. have been giving angels away since i got 30 babies from breeder , they were about 3 weeks old when i got them. read article on columnaris and am lowering temp, increasing aeration and will stop my husband from over feeding. another trip to the pet store will be required for meds. thanks for all the good info.

[Allivymar]

Sounds like you have excellent water husbandry - great! Definitely necessary in a crowded tank like that. And a 120g will help immensely; since you take such good care of the water chemistry, its likely the overcrowding that is the root of the problem. Good luck and keep us updated.