Very small fish can be stocked pretty densely, for their chemical needs: Oxygen supply, CO2 dilution, Ammonia dilution and similar concerns. In a heavily planted tank the plants will help a lot with this as long as the plants are thriving. Good water movement is important to keep all parts of the tank in optimum condition for the fish and the plants. Look at a small Danio and a same-length Cory: The Cory has about double the body mass, even though they are the same length. The Cory is a lot plumper a fish. Go by body mass, not just length when you are stocking the tank. Still, the old 1" per gallon guide is a good rough estimate to get started with. Works pretty well for fish under 2" for the chemical needs of those fish.
Remember also that the carrying capacity of a tank is not what happens when everything is going well, but what happens when the power is out.
No power means no light, so the plants will photosynthesize only to the extent that room lighting allows them. That can be significant amount if the tank is near a window, but most average room lighting is practically dark as far as photosynthesis goes (Especially when the power is out! Window lighting is not very bright away from the window).
No power means no water circulation. This means oxygen levels will get seriously depleted really fast in an over stocked tank. This is as important for the nitrifying bacteria (trapped in the filter) as it is for the fish.
A large tank like that will not cool off very fast, so temperature is the last item I would worry about in a power out situation. It can be a concern, but light for the plants and water circulation are more important.
Social issues can become a problem when you are thinking of over stocking. Research each fish species you are thinking about both for behavior within its own species and for behavior with similar species, and with significantly different species. Do not just go by closely related fish and assume the one you are thinking about will be the same. The 1" per gallon guide is of no use at all when you are considering social issues.
Hillstream Loaches evolved in fast moving water, tumbling over rocks. It is highly oxygenated water. It is cooler than many tropical tanks will be. Hillstream Loaches are not very efficient at getting the oxygen out of the water. They evolved where oxygen is overly abundant, even if they were hiding in a crack between the rocks. They are best in a dedicated tank, with that cool, highly oxygenated water flowing over rocks biotope set up with their specific needs in mind. Many Darters and Gobys evolved in similar water, so will be compatible. The best set ups for these fish are the breeder style tanks, long and low, set up with a river-like water flow. At least 20x the tank volume of turnover per hour.
Farlowella are safe with smaller fish. They spend most of their time pretending to be a stick, eating the algae and other growth on driftwood and elsewhere in the tank.
Remember also that the carrying capacity of a tank is not what happens when everything is going well, but what happens when the power is out.
No power means no light, so the plants will photosynthesize only to the extent that room lighting allows them. That can be significant amount if the tank is near a window, but most average room lighting is practically dark as far as photosynthesis goes (Especially when the power is out! Window lighting is not very bright away from the window).
No power means no water circulation. This means oxygen levels will get seriously depleted really fast in an over stocked tank. This is as important for the nitrifying bacteria (trapped in the filter) as it is for the fish.
A large tank like that will not cool off very fast, so temperature is the last item I would worry about in a power out situation. It can be a concern, but light for the plants and water circulation are more important.
Social issues can become a problem when you are thinking of over stocking. Research each fish species you are thinking about both for behavior within its own species and for behavior with similar species, and with significantly different species. Do not just go by closely related fish and assume the one you are thinking about will be the same. The 1" per gallon guide is of no use at all when you are considering social issues.
Hillstream Loaches evolved in fast moving water, tumbling over rocks. It is highly oxygenated water. It is cooler than many tropical tanks will be. Hillstream Loaches are not very efficient at getting the oxygen out of the water. They evolved where oxygen is overly abundant, even if they were hiding in a crack between the rocks. They are best in a dedicated tank, with that cool, highly oxygenated water flowing over rocks biotope set up with their specific needs in mind. Many Darters and Gobys evolved in similar water, so will be compatible. The best set ups for these fish are the breeder style tanks, long and low, set up with a river-like water flow. At least 20x the tank volume of turnover per hour.
Farlowella are safe with smaller fish. They spend most of their time pretending to be a stick, eating the algae and other growth on driftwood and elsewhere in the tank.
