Advice on fish to finish 36gallon stocking

[laur94x]

hi I've been trying to decide on a last fish to finish off my tank for a while now and I just cant make a decision so thought you lot could help me decide.

Its a 138 litre long (36gallons I think)
and currently contains
5 male guppies
5 albino cories
1 female bristlenose pleco
1 pearl gourami

Do people think I have room for 1 more fish? It definitely doesnt look overstocked, the biggest thing in there is my pleco and I think shes about fully grown at about 4/5 inches but I understand bioload is important too. Water levels are good but I have high PH where I am (about 8.2 ish I think) and cannot afford to use RO water all the time. everything seems happy and healthy though. I do weekly water changes and the tank has been set up about 5 months. I have 2 interpet filters but shall be upgrading to an external filter soon, probably a fluval 206 or 306 so wont be getting another fish till ive done that anyway.

Anyway, I'd like one more decent sized fish, not a school of smaller fishes. I like the size of my gourami. I was going to get bolivian rams but cannot find them anywhere round here and dont want to order online.
So, whats the deal with keyhole cichlids? Most places say theyre peaceful and can be kept in my sort of tank but what do people think? too risky? any info please, cant find much online about them.
Also i've just seen something called a synodontis petricola online and theyre really nice too. But i dont know a thing about them, information please?? any other suggestions on another sort of centrepiece fish? I dont want to overstock but think 1 more fish would be okay wiith what I have if people agree?
EDIT - Sorry i think i mean the dwarf/pygmy synodontis petricola if there is such a thing?

Thanks

 

[laur94x]

Anyone??

 

[NYgiantsRP]

The syno is a catfish, I would stay away from them, because you already have the cories. With the guppies, there could always be a chance of them being nipped at and maybe killed. But if you have the pearl in there and there is no troubles maybe you could try another medium sized fish. A Bolivian ram or a blue ram pair would be cool. Also keyholes are a possibility, they are usually timid. You could also do a festivum, or rainbow cichlid. Or instead of a fish, get 15 cherry shrimp, or japonica shrimp. Japonica are very cool, the longer they are in a well established tank there colors really intensify. Mine have dark green tails with white neon lines going down it.

 

[laur94x]

Thanks very much for the reply its nice to have some different suggestions. And thanks for the heads up on the catfish. The shrimp sound cool but they freak me out lol. I like the looks of keyhole cichlids and festivums but don't know if my tank is big enough?x