Last week I got 5 glofish, and 4 of them died. I let my last fish be alone for about 4 days, but felt like it was stressing him out so i got him 2 regular zebra danio tank mates. One of them is rather large, and the other is about the same size as my glofish. I'm assuming the large one is a female and my other two are males. The moment i got that larger fish into the tank my glofish started acting aggressive towards her.
First he was rubbing all over her, which i thought maybe he's just "making his intentions known" (wanting to spawn with her) But then he started chasing the other Danio around- and I can't tell if he's nipping at its tail or just chasing him around. I know that danios are playful fish, but they are not responding in kind. If they chased him back i'd feel more like they were playing, but they are trying to hide/get away from him a lot. Often all three of them get into this frenzied wrestling match and flip over each other- which really concerns me.
When i had the 5 glofish before, none of them acted like this (and i even got two of them to spawn and am now taking care of their orphan babies
I tried all manner of separation, but the glofish is just being mean! When i tried removing the glofish, the other small Danio decided it was his turn to bother the poor lady. I took her out and put her in a breeding net, just so she could relax and get some time to herself. But she jumped out of it twice and is a real pain to catch, so i didn't want to try again.
I turned the tank lights off, and covered it partially with a towel so it was dark while i still worked in my office and it seems to have calmed my glofish down a bit. I check every now and then to see how they're getting along and he still chases that little Danio, but doesn't seem so rough and tumble with the bigger one. But when i turn the lights back on he goes right back to it.
They are in a 10 gallon tank that is still in the early stages of its cycling. The nitrite levels are -just- starting to go up after the ammonia spike. The tank has been set up for just over a week. Is he acting odd because of this? I know that ideally they need a lot of swimming space, a 20g would be more what they need- but i don't have a place to put a 20gallon tank. Also i know they are good in a school of 6+ but i don't want to go spend more money on fish that are going to die during the cycling. I own a 30gallon tank that is in storage under my stairs, but as i said before i don't have space for it; and it's a lot of work to set up such a large tank on a hope that my fish is going to behave.
Am i correcting in thinking he wants to spawn with her, or is he just being rude and aggressive to the new people in his territory? I read that leaving them alone can make them territorial, and that's part of the reason i decided to get him some friends so that didn't happen. Should i have not gotten them? Should i take them back? Should i wait it out until he asserts his dominance? Should i do a water change and hope they spawn and do their thing? Will his aggressiveness pass? He is just so rough with them I'm afraid he's going to seriously injure, or kill, them.