Betta and Puffers are especially adept at this from my own experience but I’ve had many other fish recognize me. This is a behavior fishkeepers have understood for years but it’s nice to have science quantify it for us I suppose. My puffer easily recognizes my face, comes to the glass, and also treats me differently. For example, if I put my finger on the glass, he looks at it, follows it, but that’s all. If someone else does he tries to bite it. Fish like this can become as close to being pets as a fish can. Betta, because they are often kept on desktops, are also known to recognize their owners. We fishkeepers know this, but if you are interested in this – interesting – study follow the link.
The fish were highly accurate when selecting the correct face, reaching an average peak performance of 81% in the first experiment (picking the previously learned face from 44 new faces) and 86% in second experiment (in which facial features such as brightness and colour were standardized).
Source: Fish can recognize human faces, new study shows