mickey mouse fish sick

Question
I have 3 mickey mouse fish and one looks sick. he is just hanging out at the
bottom of our 20 gallon aquarium and not moving too much. his fins are
clamped shut and he has a red dot near his mouth. what does he have and
what can i do?

the tank has been set up for about a month, we have 2 swardtails, 1 angel
fish, 3 mickey mouse fish, 2 sunset fish, 2 dalmation fish, 1 shark, 1 snail, 1
beta, and 1 small "scumsucker" ( i don't know the actual name). we have
carbon filter, and from our home-testing kit, everything is at normal levels.
we change the water once a month and replace 25%. thanks for your help!

Answer
Hi Heather;

Redness usually means a bacterial infection. It would be best to isolate him to a hospital tank and change part of his water every day so he can get some rest and recover. Be sure the hospital tank holds at least 5 gallons and has air bubbles from an air pump and make sure to use a heater. Don't add a filter or decorations. If you need to use medicine at some point the filters and decorations will absorb the medicine and it will be less able to help your fish. Changing part of the water daily, 25% to 50%, will keep it fresh since there is no filter. Siphon the water from the bottom so you can get wastes out every day too. Be sure to use water conditioner every time. You could use an antibiotic in his water right away but fresh clean water and being separated so he can recover may be enough. Isolation and quiet recovery is what he really needs.

All regular tanks like your 20 gallon need a 25% water change once a week every week. Once a month isn't enough to keep water quality good and stable. Your fish will be much more healthy and live longer if you do them weekly. Good luck and I hope your little fish feels better soon...

At Your Service;
Chris Robbins