What snails are these?

[NoGi]

[zn30]

They look like Malaysian trumpet snails, not plant eaters they burrow in your substrate and turnover your substrate in the lower regions of the substrate cleaning it keeping your plants healthy. They will over populate if too much food is feed.

Also soft water will dissolve the shells, prefer conditions with African cichlids were their shells stay too hard for most cichlids.

[NoGi]

Yeah they burrow, damn crabs aren't chasing them. Will find another way to terminate.

[zn30]

They are difficult to get out of their shell so I'd say your crabs have tried and just given up. They lay their eggs in the substrate so it would be difficult for the crabs to eat the eggs as well. I think the TechDen supply snail traps unsure if they are effective as I have never used them. https://www.thetechden.com.au/Sera_Snail_Collect_and_Trap_aquarium_snails_p/es300.htm?dfw_tracker=3514-ES300&gclid=CPXrpeu-_s0CFZOSvQodjagIWQ

[NoGi]

Seem easy to catch, just chuck in some food lol

[Baccus]

In the second picture I can see what appear to be an assassin snail, these are supposed to specialise in eating snails especially MTS. I think with assassin snails you need a pair and they are slow breeding only laying one egg at a time.

Apparently No Planaria will also kill all MTS but will also kill other snails and could be harmful to shrimp, I think the jury is still undecided about the hazards to shrimp and using No Planaria.

[NoGi]

It's just the empty shell of an assassin. They didn't survive in my sula tank, not sure if it was the salt minerals or the higher temps but yeah they went the way of the dodo. Same with my micro crabs, though I suspect it was the sula salt (8.5) that they didn't like.

[Baccus]

I  actually make traps that have worked quite well in my tanks to remove MTS. I get little round tubs from the pet shop that have the fly pupae in, the tubs are like little Chinese take away containers. Anyway I drill some holes around the tub and in the lid, bait with any pellet food the snails cant resist, weigh down the tub if necessary with a small clean rock then sit back and wait for the tub to be swarming with snails. I will warn that certain demented shrimp will also get into the trap but by removing the lid and carefully tipping the water out you can separate the shrimp from the snails. I certainly found my home made job better, more effective and easier to separate shrimp from snails with. Also my traps wont allow in most fish unlike a commercially made trap that I had that rather stupid endlers got stuck in.

On other tanks that have sand substrate I use a coarse net and scoop it through the sand and then sift out the sand back into the tank while keeping the snails in the net to be disposed of.

[NoGi]

I put a handful into a recently planaria zereo treated tank which has been cleaned out and water changes etc... They lasted about a day and found them all shell into the substrate with their bodies facing up.