My poor goldfish died recently. Water quality is very good. Test kit shows 0 ammonia, 0 nitrite, and less than 5 ppm nitrate. I think he may have had an infection.
I would like to switch to tropical fish (barbs or plattys and maybe an ottos catfish or two). What should I do to my tank to prepare it for the tropical fish?
Tank: 20 gal
Filter: Aquaclear 20, Sponge, Carbon, Biomax
Airpump: Tetra Whisper, air stone
Subtrate: Pea size Gravel
Ornaments: Some silk plants and large rocks
Lighting: Flourescent hood light