A quick calculation told us the catfish are getting too big to be in a tank with this many fishes, but how big are they actually? We tried different methods:
- measuring them while holding them still (more ore less)
- putting them in a bowl of water on a scale
- putting them in a measuring cup, supposing 1 liter of fish is 1 kg of fish
- searching a table with length/weight ratio
When we knew for sure we were right, we transplanted some to the new systems in the greenhouse, so they'll have some more space.
This is the calculation:
Rule of thumb: 500 gr fish per 20 - 40 liters
Tower: 500 liters
That means: 6 - 12 kg fish per system
Currently: 275 fish per system
1 fish around 50 gr
275 x 50 = 13,7 kg