Green chromis issue?

[Randy Holmes-Farley]

I’ve had three green chromis for a bit over two months and they seem to be doing very well. There is a small one, a medium one, and a very large one. They seem to get along fine.

Today, for the first time, the medium one has a discolored (light) area along the top of its back. Not on its sides or anywhere else picture below.

Any advice?

.

 

[jonelder68]

I’m no expert but I believe it’s common for them to start having faded colors with stress or not a complete diet. When I had a few the smaller would always be less colorful. Ruled it down to aggression, being chased/charged at. I never really witnessed the aggression besides at feeding times.

 

[BonnieB]

I, too, am far from an expert. My chromis have gone through a couple of periods of lighter color vs darker over the last year but always seem to gain back the color. I stopped giving any flake/pellet for a while after reading advice to do so and that’s when I noticed the fading. While I can’t verify that was the cause/cure, when I added that back as a part of a variety of feeding regimen the color came back.

 

[Jay Hemdal]

I’ve had three green chromis for a bit over two months and they seem to be doing very well. There is a small one, a medium one, and a very large one. They seem to get along fine.

Today, for the first time, the medium one has a discolored (light) area along the top of its back. Not on its sides or anywhere else picture below.

Any advice?

.

What size tank are they in?
Do they tend to shoal with one another or keep to themselves?

Aggression would be my top concern. The location of this lighter spot is unusual, but see the couple of distinct white spots on the head? If those were on its side, that would be a major symptom of fighting.

Very often, small groups of different sized green chromis "break down". Discus often do this as well - everything goes well at first, then one by one, over months, they develop issues and die.

 

[Randy Holmes-Farley]

Thanks, Jay. They are in a 120 gallon tank with lots of hiding spaces, and are often together, but not always.

 

[Randy Holmes-Farley]

This discoloration seems to have suddenly arrived overnight as I did not notice it before, and at least at this level, would have.

There are also a number of mithrax and decorator crabs (similarly sized to the fish) as well as at least one mantis shrimp that might have pinched it.

 

[Randy Holmes-Farley]

I, too, am far from an expert. My chromis have gone through a couple of periods of lighter color vs darker over the last year but always seem to gain back the color. I stopped giving any flake/pellet for a while after reading advice to do so and that’s when I noticed the fading. While I can’t verify that was the cause/cure, when I added that back as a part of a variety of feeding regimen the color came back.

Thanks. They eat TDO chromoboost, prime reef flakes, Hikari seaweed extreme, and copepods off the front glass, as well as other bits they get in the tank. I tried fresh clam one day, but no one was interested except my LTA anemone.

 

[Jay Hemdal]

This discoloration seems to have suddenly arrived overnight as I did not notice it before, and at least at this level, would have.

There are also a number of mithrax and decorator crabs (similarly sized to the fish) as well as at least one mantis shrimp that might have pinched it.

The crabs and mantis are more likely to have interacted with the chromis from underneath, or from the side, less likely to have tagged it from above.

The same applies to some extend, to the other chromis being the culprit(s). However, the sudden onset tends to rule out a disease process.....

 

[BonnieB]

I, too, am far from an expert. My chromis have gone through a couple of periods of lighter color vs darker over the last year but always seem to gain back the color. I stopped giving any flake/pellet for a while after reading advice to do so and that’s when I noticed the fading. While I can’t verify that was the cause/cure, when I added that back as a part of a variety of feeding regimen the color came back.

Thanks. They eat TDO chromoboost, prime reef flakes, Hikari seaweed extreme, and copepods off the front glass, as well as other bits they get in the tank. I tried fresh clam one day, but no one was interested except my LTA anemone.

Once upon a time I had a mantis and that didn’t end up well for my fish…I hope Jay can advise you as he is the expert!

 

[Randy Holmes-Farley]

Thanks folks. Whether a fish issue or not, the mantis is decimating the snail population, so I will probably resume my effort to trap and sump it. I saw its beady head sticking up out of a hole in the rock this morning. Couldn’t get a good picture before it ducked back in.

 

[X-37B]

Thanks folks. Whether a fish issue or not, the mantis is decimating the snail population, so I will probably resume my effort to trap and sump it. I saw its beady head sticking up out of a hole in the rock this morning. Couldn’t get a good picture before it ducked back in.

As the food source goes away it has eaten many snails, killed all shrimp, emerald crabs, with a few strong hermits left.
Yea I have tried to catch my mantis for a year now. If you do catch it let us know how. I have the mantis trap and it steals the food without setting off the trap.
Think I will try again tonight.
My mantis hit my chalk bass twice in the eye. Several other fish with marks over the year.
I had 6 chromis in my old 120. The convict tang was the policeman of the system. When the chromis acted up the tang intervened.
Many don't realize how big a chromis can get.
My guess is the mantis popped your chromis when it swam by.
Mine will pop the hemostat when I'm in the system. If and when I can catch it it's going into the sump area I'm turning into a fuge.
Not the best pic but you can see the one extended eye.
Good luck.

 

[CHSUB]

I have rid my tank recently of 3, one remaining. Long plant scissors over hole and wait during feeding, cut in half when emerging. I would rather not kill, but my trap proved unsuccessful…and yes all my neat decorator crabs are gone…

And yes this is what Chromis do, kill each other!

 

[X-37B]

I have rid my tank recently of 3, one remaining. Long plant scissors over hole and wait during feeding, cut in half when emerging. I would rather not kill, but my trap proved unsuccessful…and yes all my neat decorator crabs are gone…

And yes this is what Chromis do, kill each other!

I have tried the hemostat method. Guess I'm to slow/old, lol.
A tank policeman helps keep them in check.

 

[CHSUB]

I have tried the hemostat method. Guess I'm to slow/old, lol.
A tank policeman helps keep them in check.

Haha yes and in your defense my tank is only 16 gallons so it is easy for me to position myself and wait!

 

[Randy Holmes-Farley]

Just closing the chapter on this green chromis issue. The fish is perfectly fine today without any apparent white area. Not sure what it was or when it “healed”, but it never seemed to cause issues and is now gone.

 

[The Gas Man]

I’ve had three green chromis for a bit over two months and they seem to be doing very well. There is a small one, a medium one, and a very large one. They seem to get along fine.

Today, for the first time, the medium one has a discolored (light) area along the top of its back. Not on its sides or anywhere else picture below.

Any advice?

.

What size tank are they in?
Do they tend to shoal with one another or keep to themselves?

Aggression would be my top concern. The location of this lighter spot is unusual, but see the couple of distinct white spots on the head? If those were on its side, that would be a major symptom of fighting.

Very often, small groups of different sized green chromis "break down". Discus often do this as well - everything goes well at first, then one by one, over months, they develop issues and die.

What do you think is a good size group for chromis?

 

[Jay Hemdal]

What do you think is a good size group for chromis?

IDK - it depends on the size of the tank. You also need to start with chromis that are all very close to the same size. I go with at least 5 in a smaller tank (100 gallon) up to 20 or so for a large tank (250 gallons +).

Given all of the inherent problems with this species (including Uronema disease and improper handling) I usually take a pass on them altogether.

 

[Randy Holmes-Farley]

FWIW, I corrected a serious typo in my last post.

"not gone" is properly "now gone". :)

As best I can tell, the three green chromis that I got from Dr Reef (who treats them before shipping) have not shown the slow die off that I've experienced with LFS green chromis in the past. It's only been a bit under 3 months, but so far so good. :)

 

[The Gas Man]

What do you think is a good size group for chromis?

IDK - it depends on the size of the tank. You also need to start with chromis that are all very close to the same size. I go with at least 5 in a smaller tank (100 gallon) up to 20 or so for a large tank (250 gallons +).

Given all of the inherent problems with this species (including Uronema disease and improper handling) I usually take a pass on them altogether.

I’m building a 75g tank now and was considering three or four. Thank you for the opinion.