Have you checked the gourami/anabantoids section first of all? There's a little info in the pinned articles. Next I suggest checking the fish index though I'm not sure if there are profiles for either of those two species (you do realise the indian gourami and opaline gourami are not the same right? - The 'indian' is colisa fasciata and the 'opaline' is trichogaster trichopterus.) You may then wish to do a search on www.google.com (my favourite research method
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) using the scientific names. Once you've done that, ask away if you have any specific questions... If you want a quick over-view of the two species:
Opaline gourami (trichogaster trichopterus)
This fish is a color morph of the three-spot gourami. Other color morphs of this species you're likely to come across are: gold(en), lavender, blue (basicaly a refined version of the wild color), platinum and cosby. Opaline is my personal favourite color though
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these fish get to 6" with males being slightly larger than females. You should avoid keeping two males in the same tank, mature fish can fight to the death otherwise. Females are relatively peaceful but will still bully each other or other gouramies. If you want to keep a group of three-spots, either go for 1 male and 2-3 or more females or a group of 4 or more females. generaly speaking, going for a group of females only is the best option if you don't plan to breed them.
Males and females have the same coloration but can be sexed by looking at body and fin shape. Females are deeper-bodied and obviously wider when viewed from above. Males have a pointed dorsal, almost double the length of that of the female. The differences become increasingly obvious with maturity and males become increasingly territorial as well.
Though these fish are usualy quite peaceful towards non-gourami tankmates, anything that might be percieved as an itnruder into their territory or that competes for space is at risk. Don't over-crowd them and make sure there is 10 gallons per three-spot.
These are the hardiest gourami and the easiest to breed but their aggression means you should be careful if you choose to keep them.
Indian gourami (colisa fasciata)
This fish is also known as the 'banded', 'giant' and 'striped' gourami. The 'giant' name can be misleading - don't confuse this fish with the true giant (osphronemus sp.) gourami. the only reason c. fasciata is reffered to as 'giant' is because it is the largest in its genus. it only gets to 4".
Again, males grow slightly larger than females. These fish can be sexed very easily by looking at their coloration as males are significantly more brightly colored with bolder stripes. They also have a more pointed and longer dorsal and anal fin. Body shape also deffers with females being wider and deeper, as with the three-spots described above.
These are a great alternative to the commonly sold dwarf gourami (colisa lalia) as they are much less prone to disease and hardier. They are also, arguably, not as territorial.
Males will co-exist peacefuly as long as they are provided with 10 gallons each at least (mainly due to size) but a trio (1 male, 2 females) is a better arrangement. As with most gouramies, avoid keeping them in pairs as the male will chase the female and stress her. Also, just because they are more peaceful than others, doesn't mean they are not territorial (females are not territorial, only the males) or cannot get aggressive. If they feel crowded or threatened they very well might turn nasty.
As far as breeding them, they aren't difficult but not as easy as three-spots. If you look up breeding dwarf gouramies, you'll find a lot more info that applies just as much to the indians or any other colisa gourami.
They also aren't picky eaters or anything but may eb shy if you don't provide them with a peaceful environment. Floating plants are much appreciated but don't let the plants completely cover the surface - both three-spots and indian gouramies need access to air - without it they'll drown.
Though the above fish can work together, it's better to stick to just one species unless you have a rather big tank. Having said that, to give you an idea - a group of 4 female three-spots and a trio of indians could just about fit in a 55 gallon but more gallons would be better.