Trumpet Snails

[star4]

I seem to have lost all but a few of my trumpet snails? One of my 3ft tanks was overrun with them so I transferred some to another tank, these are doing fine. I then transferred about 30 a couple of weeks ago into my 4ft tank. The origional 3ft tank seems to have lost all but a few tiny trumpets, there are loads of empty shells all over the tank. My 4ft tank also has a few empty shells in it and I have only found a couple of live ones. What could have killed all the trumpets but left the ramshorns and tadpole snails alone?

 

[Amunet]

What sort of fish do you have in the tanks?

 

[star4]

The 3ft tank has giant danios, small plec, cardinals and 3 kribensis fry. The 4ft has gourami's, pair kribs, rams and a pictus catfish.

 

[~T~]

Did you add anything new or any medications?

 

[star4]

I had 6 mollies a month or so ago, but they all died, dont know why no other fish were affected just the mollies, then the plants died back (just leaving new young shoots) and now the trumpets have all gone?