Over the weekend we picked up 6 blue chromis for 100 gallon tank because we wanted something that would school and swim around higher up in the tank. They were all schooling along great up until yesterday.They have split up, 2 are swimming around fine together, 2 are staying together but at the top of the tank behind the filter and other 2 hide seperately under rocks or in the corner at the bottom of the tank. I haven't noticed any bullying so I'm not sure why they changed so drastically. We have lots of hiding places, 2 clowns, a mandarin, 2 yellow coris, 2 firefish, 2 pincushion urchins, a coral banded shrimp and 2 small emereald crabs. Does anyone have any ideas on what could be wrong? We have checked the water and everything is normal.
blue chromis
- Thread starter jamie227
- Start date
ingtar_shinowa
New member
fish seldom display shoaling behaviors in a tank.
Mr tap water
New member
Hi there
I found having a few bigger fish swimming around in the tank helps keep the Shoal tighter together
I found having a few bigger fish swimming around in the tank helps keep the Shoal tighter together
gone fishin
New member
Do not be surprised if they become just one or two.
When they enter new systems, they are usually afraid and will school together. Once they become acclimated to the system, they split up because they feel secure, also this is when I see them weed each other out. If the tank is very large and open, they will school together for safety. You will have much better success at getting these fish to school if you provide a scenario in which they feel much more secure by schooling. The need for safety seems to trigger them to school. Without it, they just batman everything.
Megatrev62
New member
You need to introduce a predator for schooling behavior really. Even neon tetras won't stay together unless there is a big fish in the tank.
young_reefer
Member
+1. IME, four became three, then a few days later, became two... it has been almost 6 months since then, so I guess these two can live with each other. They even swim together and, sometimes, "kiss". Not sure what that behavior is all about but every once in a while, you'll see them kind of dancing around each other and then kissing. :lmao:
Megatrev62
New member
Strange I've had six now for 11 months, and they stay pretty tight. Time will tell I guess.
Mr tap water
New member
Hi there
You don't have to buy a predatory fish just a bigger fish something like a surgeonfish. I would also like to say it is possible to have a shoal of chromis Without them all dying on you ,I myself have 20 Green chromis For nearly a year now and stay together most of the time and I have lost a couple over the time of having them and just replace them and they was accepted Back into the shoal With no problems I think the key to success with these guys is to do with your tank Layout
You don't have to buy a predatory fish just a bigger fish something like a surgeonfish. I would also like to say it is possible to have a shoal of chromis Without them all dying on you ,I myself have 20 Green chromis For nearly a year now and stay together most of the time and I have lost a couple over the time of having them and just replace them and they was accepted Back into the shoal With no problems I think the key to success with these guys is to do with your tank Layout
Rea17
New member
I ordered 15 of these guys a year or so ago from an online retailer, and they came in small and skinny. I lost a few right away in QT, and once in the display they started grouping up near the surface of the water but still weren't thriving. They really don't eat well. I feed several times a day (5-7) and some are still fairly skinny. Some are always out in the open, some hide in the rocks constantly, and a few even hang out near the edges of the overflow and back glass.
Also, since then I've had a couple of friends give me their larger single blue chromis, and these two paired up and are inseparable. They sleep in my devil's hand leather
Sometimes they will join the school, but mostly they hang out on their own near the surface on the other side of the tank. When I get my new tank up, I think I'm going to keep the pair but rehome the others. I will likely replace them with a brighter, bolder anthias species that can be kept in large groups.
Also, since then I've had a couple of friends give me their larger single blue chromis, and these two paired up and are inseparable. They sleep in my devil's hand leather
Sometimes they will join the school, but mostly they hang out on their own near the surface on the other side of the tank. When I get my new tank up, I think I'm going to keep the pair but rehome the others. I will likely replace them with a brighter, bolder anthias species that can be kept in large groups.Yeap, mines acted just like yours the first couple of days after intro (~15 of them). Then once they felt there was no threat, then hung out separately. I had big fishes in there too (large angels, triggers, tangs). Now, all I have left are two individuals who don't really care for each other much.
Megatrev62
New member
Again I'm in the minority. Purchased 6 online last September and all survived. They are pretty tight in my 90 gallon and are thriving.
