He has ich, which is a parasitic infestation. Slowly raise the temp. to 86 degrees since parasites have 3 stages & a slight temperature increase speeds up the cycle slightly. If the tank is cycled take out the carbon because it removes meds & do a 10-25% water change (or whatever the amount is that you'd take out for a weekly change); if the tank is uncycled, do a 100% water change. For a med, I'd get RidIch @ PetSmart. It's the most effective for parasites, gentlest on fish. It can color decor though, so make sure you have non-porous items than can be cleaned to remove the blue hue that's sometimes left-glass & plastic items usually can be returned to their original color. Malachite Green is the 2nd-best med. Most other meds have copper in them which at best is very hard on fish & can sicken them & in some cases poison them.
Often, when people don't see spots they assume the parasite is gone, when the parasites are just in their "water stage" & the human eye can't see it. Treat for 3 days beyond when you see the last dots/flecks: ex. if you saw dots for 4 days, treat for 7. I normally do a 7 day round as a rule, severe infestation treatments have gone as long as 14 days. Do a 100% water change before adding meds if it's an uncycled tank, or follow the directions on the bottle for how often and what quantity of water to change if the tank is cycled. Wait 20-25 min. after doing a water change to add meds to the water, sooner dilutes them.
Sometimes parasitic infestations brings on secondary infections so watch for more coluimnaris, fungus, cloudy/enlarged eyes, shortening fins, etc. If you see any, re-post because it's a different treatment.
Most disease is caused by cold water or improper tank conditions, so make sure you have the following:
1) As a tropical fish, he needs a heater & a steady water temp. of 78 degrees 24/7. Cooler leads to stress, poor digestion, color loss, clamped fins, illness, lethargy, loss of appetite and/or death. Changes in water temp. stress him & lead to illness. Depending on the tank size he needs: 1-gallon (7.5 or 10 watt heater @ PetSmart and PetCo), 2.5-3 gallons: 25 watt heater (@ most pet stores), 5 gallons: 50 watt heater (@ most pet stores); 10 gallons: 100 watt heater (@ most pet stores).
2) Water changes remove ammonia, which is toxic and forms in the water from uneaten food, waste, breathing. It's colorless and odorless so you can't tell if the water's ok by just checking to see if it "looks" clean. For uncycled 100% water change tanks: 1 gallon: change 100% of the water (& rinse off plants, gravel, etc.) every 1-3 days; 2.5-3 gallons 2-3 times/week; 5 gallons 1-2 x's/week. If it's a cycled tank, change out 10-25% of the water and vacuum 1/3 of the gravel 1x/week; the exact amount will be based on your water test kit results.
