Have a look across the front center of the tank. I have so many goodeids inn the tank that many people would tell me it is overstocked. It is a mere 40 gallon tank but has almost 40 fish in it that average over 2 inches SL, standard length. The nitrates that I measured last week, after over 3 months since the previous water change, was only 10 ppm. My Xenotaenia resolanae, reputed to require frequent water changes always seem to prosper in the tank. It is a case of having the right growing system for plants so that I do not need to change much water since the plants absorb all plant nutrients, which are called contaminants by fish only people. It is also in conflict with the "requirements" cited by most plants only people who do not truly understand a balance between fish and plants. My tank uses fish and fish food to feed the plants which in turn do most of the heavy lifting in removing poisons, plant nutrients, from my water. The end result is that the plants prosper, the fish prosper and I only change water to reset the levels of trace minerals in my water. No fish food or fish waste can give a decent mineral recharge like a water change using tap water. That tank gets 2 to 3 water changes of around 50% each year. The small, by normal standards, water changes result in a "balanced" tank that is getting enough trace elements from the water changes and has no build of poisons in the water. It is in touch with my early years of fish keeping where everyone tried, sometimes in vain, to achieve a "balanced" tank where fish wastes were removed by plants and plants derived their nutrients from the fish wastes.
