David_

I’m a beginner, and not sure which forum to place these questions about Long-finned Zebra Danios (LZD), so I’ll start here.

1) Is there something wrong with two of them?* I purchased six LZD’s from a new batch to initiate the “nitrogen cycle” in a new 65g fresh water aquarium, with live plants.* The aquarium had been running for eight days prior to transfer, and tested: pH 6.5, NO2 < 0.3, NH3 0 (Tetra test kit).* Two days later, I noticed two of them with bright red gills.* They don’t appear to be inflamed, spotted or slimy—just bright red.* Two weeks later, all the fish are larger and appear physically normal, the tests are back to where we began two weeks ago -- and their gills are still red.

2) Does their schooling behavior appear “normal”?* One of the six died from eating a crushed snail I believe, leaving five.* They aren’t exactly schooling, as I understand the term.* They are all very active, four may be in the general vicinity of one another (mid-tank to top) with the other one swimming around the bottom, and then two will split off after being chased by the larger of the group, and not regroup again.* They never really appear as a group together.* I have read conflicting suggestions that one needs to have between six and twelve fish for them to school.* Do I need to add some more LZD’s, wait until other species of fish are added, and will the new ones naturally join their brethren or stay apart because they came to late to the party, as it were.

Thank you, I look forward to your response.

Gwenz

I'm not sure about the red gills, but i had 6 zebra danios and they never realy were schooling together. They sometimes swam together but they would split off from each other and 2 would stay together while another one would stay at the top of the tank and the other 3 swam around the bottom looking for food. I wouldn't worry too much about them not schooling together. As long as they seem healthy, i don't think it matters.

Gwenz

P.S. - Hopefully someone will be able to answer the question about the red gills for you.

aj_1992

my danios had red gills during the cycle, (p.s. i do not support using fish for cycles, it was my dad who surprised me with my original 7 danios with 2 ending up dead) i think i read somewhere that it's the ammonia and possibly the nitrites that cause the gills go red. i'm not 100% sure, but maybe wait until the cycle is done and check up on the gills again. that is unless it gets worse.

badger

Yea thats most probably some kind of poisoning, either nitrate or ammonia probably maybe chlorine, but I assume you treated the water so I doubt its chlorine or chloramine. Id guess Nitrate or ammonia poisoning as a result of the cycle.