I also feed the peas and cucumber. I pop the peas in a glass of really hot or boiling water and leave them for a while which just softens them up a bit. I shell them (I think I was told they have trouble eating the shells), and some I drop in 'whole' and some I mash in my fingers so as to give the little guys who wont visit the bottom a chance to munch.
Cucumber I just cut of an inch chunk and wiegh it down with a spare lead wieght from the plants. Clown loaches love it.
Growing courgette (zuchini) in the garden now so dont know about that one yet.
HTH