gourmi care

Question
My tank has been set up for about three months now, its 30 gallons.I had angel and cat fish at first but they died after two months. So i replaced them with 4 neon gouramis,4 dwarf gouramis,and 3 tank sharks.(from WALL-MART.}I have had 2 plecostomuses,for 2 months.I have a aqua clear,300 filter,and a current ph of 6.8.One of my dwarf gouramis just died.before it died it had black all over its bottom fin and gills.my other dwarfs have some too,and on 2 of them it has it on there heads.I would like to know if there is a sickness going through the tank.Because they were not like that when i got them.

Answer
Hi Krissy;

It may just be a natural color change. Once they settle in to a new environment and get used to each other they stake out territory and guard it. Males will get darker as a result of trying to chase off rival males. If they don't act any differently than usual I wouldn't worry about it. If they start acting abnormally, check the ammonia and nitrite in the water. They may be reacting to it by changing color due to stress. Also look for signs of disease like little tiny pin dots, greyish or whitish areas.

Followups welcome

At Your Service;
Chris Robbins