Crabs

[volvine]

Hi all
i have two questions.
1/I introduced two small crabs to my tank recently one headed straight for the inside of my filter and now resides in there and no matter how many times I fish him out he heads straight back in so I have left him to it now and he seems quite content whilst the other one lives underneath the filter my question is if he is happy living inside the filter should I leave it there I don't think it is big enough to cause any damage. 
 
2/i bought a fighting fish today ad introduced it to my tank i have come back to it a few hours later and his fins have been shredded i thought all of my fish were of the peaceful variety sso not sure what has attacked it as i have mollies tetras 2 variety's swordtails gourami's any thoughts? 
 

 

[Ninjouzata]

What sort of crab did you purchase? I don't know anything about them but imagine it may depend on what type if it'll be okay in the tank or not. Some need land.
 
I imagine this is likely what shredded your betta's tail. It's also not good to put gourami & betta together as they are similar types of fish.
 
What size tank do you have if I may ask? Do you have a heater? What temperature is it? Do you have another tank that you could move the betta to & a heater for that?

 

[Tongue_Flicker]

A couple of years ago, i discovered that semi-aquatic crabs can fully thrive underwater if there is a vigorous aeration system/air pump in the tank. Meaning a land area may not be necessary at all and they do not drown as most people thought.

What kind of crabs are they? As long as they are getting aeration/air bubbles in the filter it will be okay. Plus it will help clean your filter media as well

 

[volvine]

Hi Guys thanks for the replies I sussed out what shredded the fighting fish it was the swordtail.
also the crabs are red clawed crabs I had a piece of polystyrene floating in the tank for them although to be honest they have never bothered going on (this is what the shop had for them and they were using it in the shop anyway they seem very content I have had them now around 2 months.
my tank is a 180lt