Does anyone know if the black freshwater crabs can kill and eat fish?

I added some small catfish and mosquito fish to my pond and they slowly started to vanish, and now one month later there are none left!

They have not died, there were no bodies. They were very healthy and had no diseases and some fish had started breeding. All the water temps and OK - not too hot, and there are lots of water lotus and reeds in the pond, with floating plants also. I took some water to an aquarium shop and they tested it and told me everything was perfect with the water.

While I was searching the pond I saw a few very large freshwater crabs.

If they are to blame, how can I catch them? The pond is quite big and so full of plants I can not see where the crabs are hiding, and some parts are quite deep so I can't reach down into it without a net.

did you start your pond from new?

if not then there could be some snake head fish in there or even some large cat fish,

they both would eat whatever you put in,

the crabs would eat the dead bodys of the fish,

and dont forget that catfish can go over land to your pond, ive got net rond my pond and ive still got the odd cat in there,

jake

I agree, snake head fish, Pla Chon is the most likely culprit.

Try baiting some lines with small live frogs & leave them in the pond overnight.

and dont forget that catfish can go over land to your pond, ive got net rond my pond and ive still got the odd cat in there,

Argh, So is that why they have black plastic about 1 foot high around the big prawn ponds?

The pond is not a natural one. Its made from concrete and I built it about 3 years ago for koi carp. The carp got too large, so I converted the pond to look more natural and added the small fish to control the mosquitoes. The are no snake head fish in there for sure - noting is in there now except the crabs and lots of mosquitoes. The catfish could not get out as the pond steep sides and there is a drop of a about 5 inches before the water line.

I think the crabs climbed in and now can not get out because the sides are smooth and steep.

The pond is about 6 metres long and 2 wide.

I am going to the Chinese market tomorrow to see if they sell traps for crabs. I know they have them for eels and fish.

I hate them crabs!