Cleaner shrimps vanished

I vote with Grinder on this, thats alot of aggressive fish in a 20g. Thats about a stocking list for a 40g, maybe. I'm sorry, but I foresee more problems in your future as the maroon grows and matures, the chromis fight eachother, and the 6line goes nuts on everything. I'd be surprised if you can keep much alive with that stocking level

 

+1

 

The tank is about 1 1/2 years old
The sandbed is about 1 3/4" deep
The LR came from a good Aquarium specalist store (with hitch-hikers)
I have one hermit crab
One astraea snail died recently but did not get eaten. I have a few small ones which are a bit hard to track because of all the crevices and caves in my LR configuration.
Earlier on this year my 2 peppermint shrimp also disappeard and so did my emerald crab
I think Corailline ponted in the right direction and I may have brittle/serpent stars that are much larger than what I have noticed.

 

About the stocking level: All I can say I have currently no problems with the fish. No fighting, no harassing. No nothing.
Yes, I realize a fully grown maroon clown will be some 6".
A much larger tank is in the works.

 

I can see three brittle stars that look like serpent stars (banded arms). Don't know how large they are as I can see only the end of the arms poking from the rock crevices.

 

It would have to be a pretty large serpent star, not your typical little brittle stars. My little ones get about 2 inches.

 

Thats great that you have a larger setup in the works Walter,but defending your stocking of 6 temperamental fish in a 20g will most likely lead to an argument,the general majority of members here premotes responsible reefkeeping and 6 fish in a 20g would outweigh the amount of biological filtration necessary for keeping the water quality optimal for your salty friends,unless you have a good skimmer in a bigger sump loaded with rock or doing major wc's every other day,I don't believe you've had these fish for "years" or they would not be as small as you claim.No bashing here,just trying to help you be successful in this hobby.

 

Damsels are very aggressive, mine used to try to rip my Fire shrimp limb from limb, they were Clowns and a Yellow Tail Damsels.

A Shrimp fresh from molting or molting would not stand a chance.

Yup I agree with grinder time for an upgrade, gives everyone a little more room to hide.

 

To answer the OP's question, my vote goes to the royal gramma. They are peaceful fish until something comes near their cave. I kept one in my biocube 14, as the only fish, and i've seen him kill 3+ pepperment shrimp.

 

Is their a good lid on that tank?And do you have a cat or dog I have had a shrimp jump out of the tank at night and the first to find it was the dog the next morning.
I have since fixed that problem