Black kuhli loach details? is my ten gallon big enough to support 2? ?

The problem with Khuli Loaches is that they have to be kept in groups of 5+ for which a 10g is too small. Since they like to burrow they need sand or soft river gravel as subtrate.

Kuhli loaches reach maturity at 2 ¾ inches (7 cm) and have a maximum length of 4 inches (10 cm). This fish can live for 10+ years. The natural habitat of the kuhli loach is the sandy beds of slow-moving rivers and clean mountain streams. They are a social fish and are typically found in small clusters (they are not schooling fish but enjoy the company of their species), but are cautious and nocturnal by nature and swim near the bottom where they feed around obstacles. They natively live in a tropical climate and prefer water with a 5.5 - 6.5 pH-but will tolerate 7.0 pH in aquaria, a water hardness of 5.0 dGH, and a temperature range of 75 - 86 °F (24 - 30 °C). Kuhli Loaches are scavengers, so they will eat anything that hits the bottom. Kuhli loaches usually feed in the night time, but can be taught to be fed in the day in the home aquarium. In the wild, the fish spawn communally in very shallow water. The kuhli loach is a bottom dweller that burrows into soft places. Its ordinal name 'Acanthophthalmus' comes from the meaning 'thorn' or 'prickle-eye', after a spine beneath each eye. In an aquarium environment, especially if the gravel is suitably finely grained, Pangio species can burrow into the bottom and there remain unseen for long periods of time, emerging to eat during the night. If the gravel is later disturbed, a hobbyist might well find themselves faced with fish assumed lost a long time ago. Kuhlis may also occasionally swim into unprotected filter inlets, occasionally leading to their deaths.

Breeding in captivity requires plenty of hiding spaces and consistent water quality. And depending on the size they grow to, it's better you opt for a 15 gal tank

Good luck!

They get up to four inches, easily. Two would be about 8 inches of fish, which is almost fully stocked in a 10 Gallon.. unless you have good filtration.. still they'd prefer a longer tank because they swim FAST. so i imagine they'd be bumping their noses into the glass quite a bit. They can go with pretty much any fish as they are a bottom feeder for the most part and sand is preferred because they slide around and burrow as you said,i know id much prefer to burrow in sand than gravel - lol -

oh one more thing. they like to be in schools of at least 5, as they feel safer than if you were to get just one or two - i imagine they might hide quite a bit only having two

Yes your tank can hold 2 loach and do well with gravel substrate.