i got two WAL, one is fine unless fish decides to sit on him. I keep other with three O's no probs, but he hates all bottom dewlers... as long as mine are well feed and feel comfortable they are chilled... I think theres a lot to be said for order you add fish to a tank and the length of time you do it over. and keeping your lungs well feed definitely helps a lot! fish u dont care too much for is tankmates is best advice then if it goes wrong its no big loss...
Oh and my SAL has tankmates too....
Looking at hopefully a unidentified albino african, a MAL, a Dolloi and if it really comes in a Amphibius next week and i have just purchased two 4x2x2 double stacks so four nice 4' tanks with four solo lungs is the plan...