Help for a newby please!

[Fish rookie 07]

Hey guys I’m pretty new to this but I have had my first marine tank running for 6 months now with nothing dying yet but my scissortail dartfish has lost some bottom fin. I’m not too sure how I just noticed today I have nothing aggressive and a emerald crab but does anyone know how this may have happened and what to do about it?..

 

[fishguy242]

hi,anything else in tank besides emerald?

 

[Fish rookie 07]

hi,anything else in tank besides emerald?

Two clownfish, a sandsifter goby, two cleaner shrimp and three hermit crabs. They’ve all been there for over three months now

 

[fishguy242]

poss nipping from clownfish watch closely

 

[Fish rookie 07]

poss nipping from clownfish watch closely

I will!, the dartfish also sleeps on a side of a rock every night,could he of scraped it?

 

[fishguy242]

not likely to lose part of tail

 

[Dolphins18]

Hi did you start your tank with live rock or dry?
If you went live there could be something in there you have never seen.

 

[Dom]

Two clownfish, a sandsifter goby, two cleaner shrimp and three hermit crabs. They’ve all been there for over three months now

Clownfish are very territorial. Even when they get along with their tank mates, they can suddenly become aggressive toward something they had been getting along with.

 

[Fish rookie 07]

Hi did you start your tank with live rock or dry?
If you went live there could be something in there you have never seen.

No I went with dry as it was cheaper haha

 

[Dolphins18]

Could be the clown, but I think its more likely that you would have noticed some fin deterioration prior to this. Its unlikely the clowns did that in a matter of hours, if it happened sudden more likely a large crab especially if the fish is laying on rocks.