Can Guppy Live With Sumatra barb?

The guppy's own profile is direct about this one: it names tiger barbs specifically as a fish to avoid, because a boisterous nipper and a fish bred for long, flowing fins is the worst possible combination. Male guppies carry exactly the trailing tail the tiger barb's reputation is built on.

Water is not the issue. Both take 20 to 26 °C and pH 7 to 8 without complaint.

There is no group size or tank size that fixes the underlying mismatch: even a full shoal of 8 to 10 barbs, which keeps most of their squabbling inside the school, still leaves a slow, long finned guppy as an obvious target when they do look outward. Choose a different, finless companion for the barbs, and keep the guppies with the quiet livebearers and tetras their own profile recommends.