cheery shrimp

Hello, I have a cycled, 40 litre heavily planted (java moss, java fern, moss ball & anunbias) nano tank with an eheim powerball sponge filter, heater and thermometer. In the tank are 3 guppies, 1 zebra otto and 6 cardinal tetras, nuisance snails and until about 2 weeks ago, a thriving cherry...