Chromis

[+Grog]

Chromis

Wanted to start a chromis thread to collect information and experiences about these fish. I've read a lot of strange rumors and advice on the web, and a lot of bad press too. Things like that always make me wonder if it is accurate, or hive-mind internet behavior.

I've never kept these fish but I've considered them. I've always liked their form, movement, and colors in the LFS where I've seen them. Setting up my QT this week and want to order some fish next week. Chromis are on my short list but I'm not 100% yet.

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Shoaling/Schooling: Do yours do it? (My guess is that larger tanks and and quantities of fish result in a better percentage of this behavior being displayed.. Just a guess though.)

Varieties/Species: Which ones are you keeping or have kept? Do they mix well, or should you have one species of chromis per tank? (I'm mostly looking at the standard green ones for my tank but the Vanderbilt look cool too.)

Numbers: Rumor that I've read is to keep an odd number and that will help with fighting? True or not?

Fighting: Do they actually fight for dominance or is this a limited situation that has become overblown?

One Larger Fish: Does adding one larger chromis to a tank with chromis help decrease the in-fighting (assuming it is a real problem to begin with)

Feeding: What is the proper feeding schedule? 1X, 2X,4X,8X a day? Smaller more frequent feedings, or a couple of larger ones? (I just purchased an Eheim feeder so I should be good equipment-wise, wondering about the schedule. My guess is that several very small feedings would be best.)

QT: Is it advisable to purchase and QT the entire planned school at one time? Or add fish over the course of months? If the technique of one-larger-fish in the school is used, should it be QT together too?

[Sascha D.]

Here is my experience with some of the species.

Blue Reef Chromis (Chromis cyaneus)

I kept a group of 3 for over a year in the early 2000's.

Tanks size: 180

Shoaling/Schooling: Did not school. Group stayed spaced out by around 12" at all times, unless feeding.

Fighting: None

One Larger Fish: I kept them with 3 tangs from the start.

Feeding: Fed once a day. Nori available most of the time.

QT: I did not QT. All fish added at once.

Blue/Green Chromis (Chromis viridis)

About 4 or 5 weeks ago I added 11 Blue Chromis to my 150g. Of the initial 11, two died within the first two weeks and no losses have occured since then.

Tank size: 150

Shoaling/Schooling: All of the fish remained in a tight school for the first week after introduction. From week 2-current all fish stay within 6 inches of each other and move about the tank in groups. When feeding, all fish bunch up very closely.

Fighting: Pecking order noticible.

One Larger Fish: I added all the fish before any larger fish were introduced. Since, I have added two medium angelfish. No change in behavoir.

Feeding: For the first three weeks I fed three times per day. Week 4-current I feed mysis once per day and Marine Cuisine once per day.

QT: I did not QT. All fish added at once.

[Planeden]

Hey Grog,

I have had no trouble with my three blue chromis in my 40g tank. i always just saw and heard of them being peaceful schoolers before i bought them. after that i read some of the horror stories. so maybe you get what you expect with them. if they see that you are concerned they are going to be some sort of menace based on what you've read and do their best to fulfill it.

anyway, my biggest problem was getting them in the tank alive. went in on some group buys and got a bunch of dead ones. in three orders four were DOA, one died in QT, and two are still alive. i finally just got the third one i wanted locally (aquadome I think).

Mine school. The two that came together schooled together for about a month, then i added a third and it jumped right into the school. the clowns school with them to some extent.

Not sure about the odd/even thing. I got three due to the small tank and that was what the "minimum" school should be.

i have never seen any fighting for dominance, or even annoyed chasing i've seen with other schooling fish. i can't tell whether there is a dominate one in the group or not. it's possible i just haven't seen it.

mine are all about the same size.

i feed mine once a day with everyone else (6-7 times a week).

no advice on the QT question. i'd say it depends on the size of the QT. but i would at least put them in with a small school at a time.

i also agree with either jeeperty or saschaD that were talking about the magic chromi powers in another thread. it's also, just a general thing that i read, that schooling fish will make shy fish more comfortable. since adding them my watchman goby/pistol shrimp went from a monthly siting to a daily "i'm just going to hang out here on the sand and let wesson (shrimp) do a bunch of bull dosing. also my royal gramma is a bit more out in the open. could just be coincidence, though.

with my small tank i devoted about 1/3 of my fish space to chromis and am quite happy about it.

edit - i have had my guys two months. they are the cheapy blue-green chromis.

[jestep]

I don't think it has to be an odd number just enough to spread the bickering around. I've never been able to keep more than 1 in a small tank (sub 50 gallons). Regardless of the number, they single one out at a time until only 1 is left.

I would purchase them all at once so you can get QT and acclimation all done at the same time. I think they would be less likely to have problems if all added together as it helps prevent 1 or a group from becoming dominant and attacking new addition.

[Neon Reefer]

recently picked up three blue reef chromis from RCA to put in my 75 gal. After holding for one month in my hospital tank where they did fine. I moved them to my 75 gal display where they shoaled and schooled for about a week without disturbing the other few peaceful fish i had. Then they began to nip at each other and within 2 weeks i only had one left. in the process i can only say i wished i never put them in as they picked off my small skunk clown as well ((

And now the larger skunk clown has decided it doesn't like the surviving chromis and is chasing and nipping at it , so i imagigine in no time I will have 0 chromis. I should have gone with the flasher Wrasse which was my first thought.

[Wade]

I've kept blue chromis for past couple of years. I had a group of three because I also heard that its best to get an odd number. Two died within a few months and I can't positively say it was one killing off the others, but they did pick on each other and never really schooled. I went and got a couple more (green) and added them to the tank. They were about half the size. The new tried to buddy up with the existing gone and he terrorized the heck out of them. Killed one in about two days and the other just out maneuvered him for about two weeks until the big one finally accepted him.

[Timfish]

I've been generally disappointed with chromis. Seems like there's always an aggressive one and I end up with one or that harasses the others so they're not schooling and the only time I had a school was because I ended up with two males that just didn't leave the main group any space.

[Wade]

I would pull mine out if I could catch him and throw him in the QT. They're a booger to catch!

[FarmerTy]

Realized I never added to this base of experience:

3 Years Ago:

Added 11 Blue Chromis to my 125g about 3 years ago.

Tank size: 125

Shoaling/Schooling: All fish schooled initially.

Fighting: No fighting or pecking order noticeable. They were all roughly the same size.

One Larger Fish: All same size.

Feeding: Rotated flakes, pellets, and frozen and fed once a day or every other day.

QT: I did not QT. All fish added at once.

Result: Initally all chromis schooled together, but over the course of 6 months, they slowly died off one by one until there were only 3 left. Those 3 survived for 1.5 years before they started swimming off by themselves and stopped eating and died. None survived.

Present:

Ordered 10 from Reefs2Go about 3-4 months ago

Tank size: 125

Shoaling/Schooling: All fish schooled initially.

Fighting: Fighting and pecking order noticeable. The two larger ones definitely let the others know who's boss.

One Larger Fish: Two slightly larger than the rest.

Feeding: Rotated flakes, pellets, and frozen and fed 2x a day.

QT: 2 died in QT immediately, 1 died later in QT. The remaining 7 fish added at once to main display.

Result: 7 still going strong.

Some observations:

1) Feeding 2x/day seems to cull aggression a bit. As I have noticed that when I miss a day or don't feed 2x a day, they tend to fight and bicker more in the group.

2) Interesting observation during the holidays... was not able to feed the fish for about 2 days and on the 3rd day, one chromis was missing. I found him hiding in an acro colony and separate from the rest of the group. He happened to be one of the smaller chromis as well. I suspect that the lack of food caused them to turn on each other and fight more. Naturally, the smallest one got picked on the most and thought it was in his better interest to separate from the pack and hide in the acro colony until better times came around. It's been about a week now of normal feeding and he is still not swimming with the pack. He comes out to eat but then goes back to the colony for safety afterwards. I'll update if this changes.

3) My little SPS frags are large enough now that they can actually be used as protection. I think perhaps my original group of chromis may have had more of a chance of survival if I had these same colonies back then.

Isolated from the group during feeding (he's on the left by himself)

Can you spot the chromis? Cause he's got his eye on you!

[Wade]

@Jeeper: Man that's a beautiful tank! That picture of the chromis peeking out of the acro should be entered in a competition:)

[FarmerTy]

Haha. That's not a bad idea Wade. I did take those with my phone so it would apply.

[Wade]

How do you keep the zoas from overtaking everything? Will they only grow so high into the next PAR level or do they just stop when they meet another coral? I was kinda worried about them spreading all over and maybe killing whatever they come in contact with (like an encrusting monti or acro, but you've got like a blanket of them and it looks like everything is playing nice nice.

[FarmerTy]

Double post

[FarmerTy]

Most of my zoas are on large flat rocks on the sandbed. They just grow to the limits of the rock. The ones that share rocks with my sps or lps have always lost the territory battle so I don't worry about them spreading.

The height differential helps too, as my SPS are more akin to the trees in the forest and the zoas are like shrubs... if that makes any sense.

[Wade]

Makes perfect sense. Good to know that the SPS and LPS will keep them at bay.