They are EXTREMELY hard to get rid of because they lay bombproof eggs, stuffed in little crevices. Drying, concentrated acids, concentrated bases, concentrated bleach and anaerobic conditions do not bother the eggs. I have tried all of that. Furthermore, the eggs have variable hatching times of who knows how long---up to at least a couple of years. About the only way to get rid of them is to keep fish or other critters that eat every one that hatches and keep them for about 3 years. I think that by three years all the eggs will have hatched. Another way might be to remove all the inside silicone , scrub thoroughly, and re-silicone the tank. Possibly heating the tank to near-boiling might do it; I have not tried that yet. Be glad you have the little ones and not the big ones that eat plants!