I have offically set up a new 75 gallon.I am going to add my 5 inch reddevil from my 29 gallon.what else could i add.If i added another reddevil close to its size would they be able to stay in there together for life.
They could or they couldn't it all depends on the personality of the individual fish, but in my opinion that is to small a tank for two fully grown Red Devils. And also is the new tank cycled yet if not I would cycle it first.
to be honest I would not add another red devi, they are notoriusly aggressive and adding another one would just start world war III and a half : IF you must insist on adding one add a male the same size or just a smidge bigger then her but I still wouldnt recommend it since the only sure fire way to get red devils to spawn is top let them grow up together and even then their is a chance that things might get ugly like when I had two reds male, female they grew up and mated about six times and then the male just up and decided to kill her for no apperent reason. anyway I am just putting in my two and a half cents hope everything goes great.
unfortunately, you've chosen one of the most aggressive cichlids of Central America. IMO, the chances of two of them, whether male or famale, living amicably in a 75 gallon tank are exceedingly small. almost zero i'd say.
had you grown them up together in a group of juveniles and they formed a "pair" themselves, you 'might' stand a chance, albeit temporarily. as managuay has said, they might live together fine for a time and then one morning you'd wake up and find the female dead.
I plan on buying two 4 inch reddevils so i most likely will end up with a male then when they pair up i would put the other rd in a 55.I actually bought my female last november out of town at supreme pets for $8 and she was really healthy and fat.9 months later she is in a 29 gallon and soon to be in my 75 this week when my 75 gallon cycles.I bet she will be happy.In my 75 gallon i added a whole bottle of aquasafe,and 5 teaspoons of cichlid salt.
perhaps you didn't understand my post, so let me try again. if you buy two more devils and end up with one male (no guarantee) ... and then you place that male in the tank with the female ... the male is going to kill the female. when buying two devils, you're just as likely to end up with two males in which case one will likely kill the other.
if you want to breed this cichlid here's what i'd recommend. grow about 5-7 juveniles up together in at least 75 gallons and allow one pair to form from that group. then remove all the rest of the unpaired cichlids. at this point it would be helpful to add a group of target fish ... some small, feisty cichlids such as convicts would work well. have as many caves in the tank as you have target fish and make certain that these caves are sized such that the convicts can fit in them but the devils cannot.
target fish 'can' take some of the pressure off the female. another option is to used an egg crate divider. (those plastic fluorescent grating contraptions that allow you to separate a male and female in the same tank). this is called an incomplete divider. when there's a large enough disparity in size between males and females, most hobbyists cut two square "holes" in the grating such that the female can pass through from one side to the other but the male cannot. this way, the female can make forays over to the males side and if they're spawning cycles are concurrent, they will do so ammicably. if they are not, the female can scurry over to her side again and avoid the males aggression.
in some cases, males and females never get along in the confines of an aquarium and no holes are cut in the divider. this is called a complete divider. the male and female can spawn .. usually on a flat surface placed right up against the divider on the females side. she will lay her eggs and the male will fertilize them right through the openings in the divider. though not all eggs will get fertilized using this method, you'd be surprised how many actually do and many successful spawns of extremely aggressive cichlids are accomplished this way. umbriferous come to mind.
if by spotted catfish you mean Baryancistrus sp., then yes, they'd be perfect. if on the other hand you mean Corydoras punctatus, i have my doubts. why? the former, grows to about 5 inches and won't be perceived as either a threat or lunch by Amphilophus labiatus. corydoras on the other hand are little guys and may get nipped at by the devil.