What can I use for fertilizer for my freshwater aquarium plant?

Laterite in its pure form can be used as a fertilizer for freshwater aquarium plants. Pure laterite is a clay substrate that can be mixed in the aquarium gravel for constant fertilizing.

In addition to substrates like laterite, liquid or tablet fertilizers can also be used. Liquid plant fertilizer is good to use if the freshwater plant needs immediate fertilization due to weak stems or unhealthy leaves. Tablet fertilizers are slow-release fertilizers. Place tablet fertilizers in the bottom of the fish tank in open areas. Once the tablets melt, replace them with fresh ones. New fertilization is necessary each time the tank water is changed.