Currently 7 tanks active, personal high is 12.
At the moment:
2 X 10 gallon with livebearers and plants
1 X 15 gallon with 2 diamond tetras and a juvenile pair of PS polit (brand new species to the hobby)
1 X 20 gallon with a breeding pair of Kribensis (and 2 fry)
and a 65 gallon divided in half and a closed section forming a shelf with rock piled on it, that makes an easy to capture breeding/grow out tank for cichilds (unlike "Amphibious" I like Africans, we have really hard water here and they do well in it). One side has a colony of a Lamprologus shell dweller a half dozen adults with about 20 fry and the other side is a grow out tank for my Forntosa
The above are all upstairs in my home office in a steel 48" X 18" X 72" rack
And in the living room, my main display tank is a 75 gallon with a breeding pair of Cyphtilapia frontosa. Male is about 10 inches, female about 8.5" and currently 14 fry that are almost big enough to try netting and move to the grow out tank. It's got about 100 pounds of rock to provide hiding places.
Also spread thoughout my tanks are a number of Clown loaches (for snail control) and Bristlenose Plecos (dwarf species, max about 3", great algae eaters)