I have had my neons for about 18 months but my tank has been established for nearly 3 years. For the last couple of months I've noticed that one of them is a lot skinnier than the others. His behaviour isn't different but he did seem to find it difficult to eat bigger bits of food so I now make sure to crush flakes a bit. Should I be concerned or does he look ok? Thanks It is the fish in the middle at the bottom More pics...they're a bit blurrier though!View attachment 429447 View attachment 429448 Forgot to say my levels are fine 0 ammonia 0 Nitrites 40 nitrates (tap water has high nitrates).