little creatures in my tank.

[mbtulimaa]

Hello to all,
I am new to this forum and I have only had my tank for 4 months. I have a 20 gal saltwater reef tank. I have recently noticed these little creatures that I am concerned about. They are greyish in appearance, rectanglish in form and they kind of pop their butts up when they deficate. They are approx .25 inch long. They seem to be some sort of strange crustation. almost like a rolly poly bug of the sea floor. They are all over my tank. Are they naughty or nice? Should I get some sort of wrasse or manderin goby to keep them down. Will they eat my corals or sponges? I currently have 2 false perculas and 2 blue-green chromis and LOTS of inverts, as well as 4 turbo snails. Any help would be greatly appreciated.
Sincerely,
Amy L. Cone

 

[ophiura]

Welcome to the board!
I suspect the creatures you are talking about are amphipods (but don't have a good picture right now). In general, they are quite desirable critters in a tank, and very handy part of a sand bed and clean up crew. There are some nastier bugs out there, but I don't think it is likely that you have these.
Definitely do not get a mandarin goby for that size tank! I think you are maxed out on fish and any more might upset the balance! Plus, they are not critters that need to be controlled

 

[bang guy]

The larger bugs in this pic are Munnid Isopods. Do they resemble your bug? They are beneficial as Ophiura stated.

 

[jonthefb]

if they look like a rolly poly, they are probably gammarid amphipods....totally harmless guys that are a great source of food for many fish!
good luck
jon

 

[serpentine5]

Great pic Bang Guy

 

[primas]

actually bang guy.. i have the really small creatures in my tank .. th eones shown in ur pic.. wat is that and how have they gotten in my tank?... ive had my tank for over 3 yrs.. and this si the 1st time i have seen them...here is my post from another forrum
can anyon tell me what these little tiny tiny flea looking things .. maybe dark yellow in color .. are crawling over the walls of my tank...ive had my tank for 3 yrs now and have never seens these... is this detrimental to my tank?... i have a 50 gallon with only a blue tang and 2 clowns... FO tank ... please help.. i just noticed them this morning becuz they are so small.. but they are moving and alive

 

[bang guy]

The small bugs in the pic are benthic Harpacticoid Copepods. Very beneficial. They could have come in on anything. The population will rise and fall depending on the food supply and # of predators.

 

[sammystingray]

I've noticed that isopods and amphipods look quite alike when photographed from underneath.....my amphipods look just like that almost, until you look at them from above or the side. Maybe minor differences, but to an untrained eye like mine......very close.