This is why they are near impossible to captive breed. The mear hobbiest does not have this
"Pond is about 20' by 14' by 4.5'. Filtering thru' a sump of about 8' by 4' by 5' dept with 4 compartments. Water from last compartment then flow thru' a 20' by 2' by 3' long drain with many plants back...