Kuhli loaches are peaceful and make great tank mates for guppies. Both fish are natural omnivores and will eat the same type of food. The problem is guppies reproduce fast and can easily overpopulate the tank if you put both male and female guppies in the same tank.
Apart from that, you might wonder if guppy fry will be safe in a community tank with kuhli loaches. Will the loaches eat them?
Kuhli loaches will eat guppy fry at the bottom of the tank. Since they are scavengers that scour the bottom of the tank for pretty much anything, they will eat small guppy fry that fit into their mouths soon after they’re born.
Kuhlis will also scavenge and eat insect larvae, small-sized crustaceans, and eggs of other fish in the aquarium. Therefore, I do not recommend having kuhli loaches and guppy fry in the same tank.

Do kuhli loaches hunt guppy fry?
Kuhli loaches will not actively hunt guppy fry for food. These fish are characteristically bottom dwellers while guppies swim close to the top of the tank all the time.
However, guppies give birth by dropping their fry into the water. The fry sink to the bottom of the tank (where kuhli loaches dwell) and stay there for a couple of hours to acclimate before swimming around the tank.
This is where the problem arises.
Unfed, hungry kuhli loaches will not hunt guppy fry, but they’ll eat them if they swim or sit at the bottom of the tank. Until the fry grow to a bigger size or start swimming away from the bottom of the aquarium, they are at risk of being eaten.
I advise that you move your pregnant guppy to a breeding tank before it gives birth to protect the babies from being eaten by larger fish in the community tank.
However, they are not predators and will only eat them if an opportunity presents itself.
The feeding habits of kuhli loaches
Scavenging omnivores
Kuhli loaches are scavengers and a great clean-up crew for a tank. They will use their barbell to probe the substrate and eat any leftover food.
In the wild, kuhli coaches are omnivores and will feed on both meat and plant but largely, their diet consists of protein like dead fish, small crustaceans, and larvae. Therefore it is essential to give a similar diet in captivity.
Aquarium diet
There is plenty of food you can feed your kuhli loaches, including fish flakes, live or frozen blood worms, black worms, sinking pellets, brine shrimp, flake food, algae tablet, live daphnia, Mysis shrimp, tubifex worms, frozen foods, and any meaty food.
Kuhli loaches will also eat vegetables such as cucumber, carrots, zucchini, peas, squash, sweet potatoes, spinach, lettuce, and kales. You can feed them either cooked or raw vegetables.
Sinking foods are the best
Give them sinking food because they mostly stay at the bottom, and the top swimmer fish will eat all the food. Even when it reaches for the food, it can get stomach upsets due to swallowing air as it eats floating food.
When can kuhli loaches prey on guppy fry?
Kuhli loaches are bottom dwellers and will spend most of their time burrowing on the substrate rather than swimming up. Guppies and their fries, on the other hand, are top dwellers. Therefore chances of a guppy fry and kuhli loach meeting are very slim.
The only time that a kuhli loach is likely to eat guppy fry is right after birth because when at birth, their mother will rise close to the surface and drop them in the water.
The babies will fall and lay on the substrate for a few hours as they adjust to the water and gain strength. During this time, guppy fry are vulnerable and are likely to be eaten by the kuhli loach as it looks for food on the substrate.
However, if the fry can survive a few hours, the chances of being eaten by the kuhli loach will reduce. The guppy fry will start swimming upwards a few hours after birth and might not bump into the kuhli loach again. The guppy fries will also learn to hide and swim faster.
How to keep guppy fry safe in a community tank
If you have guppies as tank mates for kuhli loaches, you might want to consider just male or female guppy fish because community tanks are not the best for breeding fish. However, if it happens that you have a pregnant guppy in the tank, you can do a few things to ensure the fry won’t get eaten by predator fish.
If you do not have a breeding box or a separate tank to rear the fries, you can do the following to increase their survival rate in a community tank.
1. Provide a lot of hiding places
Guppy fry are vulnerable in a community tank. However, they will stand a chance if you put up hiding places. After birth, they will lay on the substrate where they are likely to be eaten by bottom dwellers like the kuhli loaches.
A few hours later, they can swim faster and hide. You should put live plants, rocks, and decorations where the small guppy fry can hide without being spotted.
2. Have a big tank
A small tank will have few hiding places, and the young guppies will keep bumping into the other fish, which will eat them. A big tank will allow you to put many hiding places, which are ideal for a community tank with guppy fries.
3. Feed your kuhli loaches sufficiently
Some fish will only eat guppy fry when hungry because the fries are very small, and the fish will see them as food. The fries are also a target because they cannot put up a fight. If you give the fish enough food, you will minimize the chances of eating the guppy fries.
Conclusion
Kuhli loaches will eat guppy fry if they can find them, but they will not actively hunt for them in the tank. To protect guppy fry from being eaten by kuhli loaches, keep them in separate tanks, keep your loaches well-fed so they won’t be tempted to eat the fry, and provide plenty of hiding places for the fry.