Fish Fertilizer is a good source of nitrogen. Seaweed extract is a hormone and not a fertilizer. If you are growing bananas for fruit, you'll need a significant source of potash, such as Sul-Po-Mag. Don't use muriate of potash, it is a significant source of chlorine which will harm your plants in the long run. Banana peels are impractical as a fertilizer, you'll need about 3,000 per per plant per year. See this prior thread for more details:
Banana Peels.