Hi all, New to the forum and am having some problems with my new 20g tank. Didn't know about cycling when I started it 10 days ago, and am of course learning through the unfortunate deaths of my fish Currently in the 20g I have 5 neon tetras, 5 black neon tetras, 1 baby bristlenose pleco (1.5 inches) and 1 baby clown pleco (2 inches). There is driftwood, fake plants and a cave in the tank. Unfortunately since starting this tank I have lost 2 neons (sucked into the Aquaclear 20g filter - found one swimming in the filter alive but it later died). I now have prefilters installed on all my filters (both the 6g and 20g tanks) Last night I noticed that 3 of the black neons had broken away from the main group and were swimming at the surface. The other black neons schooled with the neon tetras and were all fine. Today 1 black neon was dead and 1 was in poor shape so I had to euthanise it. And when I returned from work this evening, the 3rd lone swimmer was dead too. I thought I noticed small white spots on one of the dead black neons and figured ich might have broken out so I raised the temperature of the water to 30deg today, and since my 20g was being filtered by an Aquaclear 20 I bought an Aquaclear 70 and set it on "low" to add to the filtration plus installed an airstone. Now one of the other black neons is swimming at the surface. He seems to swim there, dart away, play in the current of the Aquaclear 70 then return near the surface again. He doesn't seem agitated and isn't swimming abnormally but I don't know if this top-dwelling proclivity is a sign of trouble. He is not schooling with the other tetras. Not too sure what else I can do. My water parameters are: ammonia 0.25, nitrites 0, nitrates 5. I do daily 20-25% water changes with added Seachem Prime because of the plecos (which will be rehomed in a new 55 or 60 gallon in the next few months - haven't decided which size to go for) Should I be worried about my black neon loner? Is an Aquaclear 70 too powerful a current generator for a 20g tank? I am running it together with the Aquaclear 20 I already had in place since I figured any bacteria I had in that one would be wasted if I took the 20 off. Any ideas? Or do black neons simply like to freak their people out?