Black Widows

We have five of these guys at the moment, the sixth went AWOL a while ago. They don't form a shoal (the recommendation for tetras is always to let them 'be happy' in a shoal) but instead just swim around willy nilly in a never-ending quest for food. Of the others, we have an assortment of single tetras (shoal remainders!), a single danio and a single, very large upside-down catfish. Today though, we've been on the lookout for the shrimps and have spotted two of the five added yesterday. There's also something that looks remarkably like a shrimp shell but that might be a pessimistic appraisal, here's hoping they all survived their first night in the dark, underwater jungle.