Starfish being eaten?

[i found nemo]

I have a Serpent Starfish in my tank that has been in there for about two months. He is at the front of the tank with what appears to be bite wounds right next to two of his legs. He is still alive but doesn't look like he will be for much longer. I have a small red legged hermit crab that was just added last week and he seems to be the only one near the starfish and it looks like he might be the one that did this. Is this possible for a such a small hermit crab to kill a starfish? The starish was fine yesterday and was climbing around on the rock :unsure:

The other things in my tank are:

cleaner shrimp
2 clownfish
2 blue damsels
1 blue hippo tang

What could be doing this?

 

[thanh386]

Could be he got wounded somehow and now the hermits are picking at it.

 

[smallblock]

how big is the tank?

 

[i found nemo]

40 gallon and he didn't look sick or anything. He was perfectly fine when I turned the light off late last night.

 

[i found nemo]

I think this must have something to do with my water. I just found one dead hermit and a dead snail???

 

[brianjfinn]

I Found Nemo;560794 wrote: I think this must have something to do with my water. I just found one dead hermit and a dead snail???

I was going to say it could be an issue with a hitch hiker, but after this statement, it definitely could be a water issue. Give us more information on your setup, and someone around here might be able to diagnose the issue.

How long have you been in the hobby?

How long has this system been set up?

What is your water temp?

Test the following parameters and let us know what type of test kit you use:
Ammonia
Nitrite
Nitrate
Phosphate
Specific Gravity/Salinity

Hopefully he's not too damaged and can pull through. Good luck!

 

[i found nemo]

I always have my water tested at the LFS and they are not opened today. I will have to go buy a test kit tomorrow and have them test my water. I have had it set up for about 2-3 months but the starfish was one of the first additions and was perfectly fine until now. I took him out of the water because he was a goner. The fish and the last hermit were already devouring him.

Water temp is set at 78 and stays around 76-78

 

[brianjfinn]

OK, sounds good. Sorry about the loss! When you go buy a kit, make sure you get a good quality brand. You may hear from some people that like API, but I have never had good results with them. Salifert and Elos are more expensive, but you get a good accurate reading, and more peace of mind. When was the last time you did a water change?

Also, how big is the tang? Tangs can quickly outgrow their systems, and when full grown may need more swimming room than a 40 gallon can provide.

 

[cr500_af]

Did you recently do anything (such as a water change) before all of this started? I'm wondering about a rapid salinity change (such as improperly mixed water-change water) since inverts like starfish are very sensitive to that situation. Fish will sometimes show no signs of distress if the SG changes quickly, but inverts often die without slow acclimation.

And, at risk of sounding like the Tang Police, at some point that Hippo will be way too big for a 40g tank, assuming it has enough room now. You'll need to rehome it eventually.

 

[i found nemo]

It was the salinity going up as the water was evaporating. It was too high so I am now in the process of slowly getting it back where it should be. The Hippo Tang is very small, maybe an inch and a half or so. I am going to get a bigger tank as soon as I save up some extra money This is just for starters and I wanted to start with something on the smaller scale.

 

[cr500_af]

The salinity rising due to evaporation is a slow process... more than slow enough to let the animals acclimate to it. That is assuming it didn't, over time, get so out of whack that they just couldn't live at that salinity at all (which I doubt is the case).

 

[i found nemo]

Well the salinity was at the very top of the hydrometer. So I don't know exactly how bad it was. Would that have any effect on the hermits and snails as well? Also, one of the fish died, so I know it has to be something with the water. I searched around for hitchhikers and didn't find anything.

 

[cr500_af]

Possibly. Invertebrates are more sensitive to salinity change; they may also be more sensitive to overall salinity numbers in general (though I'm not sure on that part).