The other guys touched on the major stuff.
Keep a strong group of microbes going to digest your amendments. Use compost or worm castings top dress, or Recharge or Tea something every couple of weeks to get more bacterias.
You can use a couple (like 2) Teaspoons of Molasses per 5 gallon bucket of water as a food source for your microbes. The molasses can go in the tea to feed microbes as you brew. Or you can water it into your soil after compost/EWC top dresses.
- maybe it's also possible to add a little molasses to your nutrient teas, to provide sugar for microbes. Theoretically the sugar could help the bacteria in your soil reproduce, and theoretically these extra microbes could help break down the nutrients in your tea so they're more usable by the plant.
You can also use humic or fulvic acid to help make nutrients in your soil easier to uptake more available.to your plants. You can use some kind of commercial product from the store. Or you can rely on natural humates in compost and just top dress with some regularly.
Your fish fertilizer has Nitrogen in the form of Amino Acids. Some of these amino acids make micronutrients more absorbable by plants. Some amino acids even stimulate your plants to take up More nutrients than they normally would. So in addition to using the fish fertilizer to address nitrogen deficiencies in your plant, Think about micro-dosing regularly with small amounts just make your nutrients more available.
What's up with your plants? Are you just starting out in veg? 3 weeks into flower? If they're small and young you shouldn't mess with them much. If they're bigger and older and have been depleting the soil in their pots for awhile you'll need to do more.