Baccus said:They look like bite marks, what other fish are in the tank?
from http/www.practicalfishkeeping.co.uk/content.php?sid=6079
Infection rates in people are low. In the USofA, where they seem to get it a bit more than in the UK, the rate (for all cases, not just aquaria) is around 0.27 infections per 100,000 population. In the UK, the current rate of murder is 1.22 per 100,000 population. So, you’re likelier to be killed by a loon with a machine gun than catch it. It’s pretty rare.