You should limit your portions of fish to at least two portions of fish per week for a healthy diet.
You could eat a little more fish per week but avoid eating too much because you could get mercury poisoning from too much fish in your diet which is not good for you at all.
Fish is a good food and can help and promote brain health but never eat too much of it.
Some Fish that have high levels of mercury are the king mackerel, marlin, orange roughy, shark, swordfish, tilefish, and ahi and bigeye tuna.