I've used 5 and 10 gallon tanks as my mainstays for raising apistos for the past 17 years. I've had good spawnings from smaller fish like A. borelli as well as larger fish such as A. nijsseni. I always let the parents raise the fry. I do have fairly heavily planted tanks and this probably helps with hiding places. David Soares is always lecturing me about my tanks but larger tanks would be difficult to keep supplied with r/o water. I read with interest the earlier thread regarding using an ion exchange method of getting "soft" water. Exchanging Ca with Na did not work for me at all. My fish just gradually withered away. R/O works well and if you start with good water it is even better. Tom