Tiger barbs have a bad rep which is somewhat deserved. They are nippy by nature and when kept alone or in small groups they will no doubt nip on other fish. In my experience when kept in large groups though 10+ they rarely bother other species. However you should still avoid keeping them with timid species. The barbs swim fast and dart around (which is great for the people watching them (and is why I prefer them over tetras). But the sudden moments can be intimidating to other fish.
I love barbs and find them to be great aquarium fish. Avoid species which will get too large for your tank (tinfoil barbs do get very large). Because of their active nature I'd say make sure your tank is 1 foot long for every inch long the barb is. So in a 75 gallon look for fish which would max out at 4 inches.
Most barbs set a social structure which seems to be based around chasing each other so it's typically best to keep them in groups to nurture this instinct. Otherwise they will likely recruit other tank members into the society of chasing.
I keep most of my loaches with Barbs by design. Many loaches will be hesitant to come out unless they feel the coast is clear. In my oponion having active fish throwing a chase party in the top to mid levels of the tank shows the loaches that the coast is clear. So the loaches will be more likely to come out. Also most barbs can stand up to the large amount of water movement which many loaches prefer.
I'm currently keeping Arulius barbs with Kubotai and Straita Botia loaches. Odessa barbs with my Dojo Loaches. And at one point I was keeping Tiger barbs with Dwarf Botia. I also currently have a school of Pentazoa barbs sharing a tank with a pair of breeding plecos. The barbs leave the fry alone. I'm sure a larger barb species would eat the fry but these guys ignore them.
Anyway that's the end of my rant
Check out some of the great articles on this site.
http://www.loaches.com/articles/oxygen-in-the-aquarium
http://www.loaches.com/articles/an-intr ... ping-botia
http://www.loaches.com/articles/river-t ... old-design
And make sure you research any species before purchasing.
BTW a 8 foot long tank full of tinfoil barbs and clown loaches would be awesome

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