I often find these blighters inside of my outside ponds and then wonder how much damage they have done by the time I discover them.... I'm sure if they go undetected, they can (substantially) reduce the numbers of my outside Guppies and may even go for the Convicts???.... They are a nuiscance around here and also leads to the prescence of Ringnecked Cobras, which I have also seen around my ponds...... The dangers (and joys) of keeping fish!!