If you're looking for a Fishbrain alternative, FAIND takes a different tack by using AI to match people with like-minded people in their area. The app is geared toward finding like-minded people for your hobby, so it could be a good option for anglers who want to find others who share their enthusiasm for fishing.
Although not a fishing app per se, Safewaters.ai uses deep learning algorithms to predict shark activity, which might be of interest to people concerned about marine safety. Its primary purpose is to predict shark risk, but its AI approach could offer some useful information to people who spend time in the water.
For a social twist, Waverly is a platform that uses conversational AI to connect people with like-minded people. By creating custom spaces and suggesting AI-generated content, Waverly encourages meaningful connections. That could be of interest if you want a community along with your fishing.