For feeding crabs are used…
The process of feeding any animals, as is well known, is one of the most enjoyable moments in home keeping. This applies, of course, to crabs as well, which are best fed on land by placing food in their usual resting spots. Firstly, you will treat yourself to a fascinating spectacle, and secondly, the water will be less polluted. But they also act as good “scavengers” in the water, picking up what has fallen to the bottom of the aquarium.
Regarding diet, crabs are generally undemanding. High-quality sinking pellet food for aquarium fish is good to use as a basic diet. Gammarus, bloodworms, and tubifex are eaten with appetite. From time to time, you can supplement the little crabs with dry Gammarus or Daphnia. The diet should include finely chopped vegetables, fruits, and seafood (fish meat, crustaceans, and mollusks). Crabs really love pieces of fish, but do not refuse cucumbers and boiled carrots either. Small pieces of these treats can be carefully placed in front of them on the island.
The most common species of crabs are omnivorous, with a tendency towards meat food, they do not eat carrion, but only recently deceased animals. Carnivorous crabs: Limnopilos nayanetri, Parathelphusa pantherina, Potamonautes lirrangiensis, crabs of the genus Geosesarma (except G. notophorum and G. krathing, which are omnivorous). A varied diet is mandatory. An essential part of the diet of any crab in an paludarium/aquaterrarium (including carnivorous species) is autumn brown leaves, both in water and on land. Crushed eggshells or calcium powder serve as a source of calcium for crabs. Where to put the food — in the water or perhaps on the substrate — you will quickly figure out where the animals prefer to eat. Fruits and vegetables must be peeled, scalded, or even slightly boiled, especially for small crabs. The amount of food should always be adapted to the size of the animals and the size of the group — too much food will affect water quality.
For feeding crabs are used: Apple, melon, pumpkin, cucumbers, beets, carrots, red pepper, zucchini, cauliflower (including leaves), broccoli, green peas, cabbage, lettuce, corn, celery leaves, asparagus, spinach, zucchini. Dried leaves of maple, nettle, oak (leaves and bark), raspberry, hazel, nasturtium, calendula, clover, dandelion, almond, brown autumn leaves of European trees. Fish, shrimp, squid, mussels, crustaceans, snails, bloodworms, frozen foods (black, white, and red mosquito larvae, daphnia, cyclops). Pellet fish food, flakes, turtle food, oatmeal, crushed walnuts, coconuts, spirulina, groats, cornmeal, fish oil. Meat of terrestrial vertebrates, starchy and sweet fruits and vegetables, potatoes, pasta, bananas, and other sweet fruits are strictly forbidden for feeding.
It should be remembered that almost all crabs do not “hesitate” to obtain food through predation, attacking other animals, including other crabs, especially after molting. Therefore, it is best to keep crabs separately. And if a crab does not live alone, the terrarium must have shelters where molted crabs can hide until their shell hardens. Caucasian crabs are considered more carnivorous than Crimean ones, whose diet is dominated by plants (they have even been spotted eating leaves fallen into the water). But in general, the composition of food changes seasonally, depending on its abundance. Crabs easily get along with many not-too-large fish.
All of the above suggests that keeping crabs in captivity is not a completely simple and ordinary activity. It requires certain efforts. Will you be able to create conditions for this “beast” so that it feels good? No matter how funny and attractive the little crab looks in a pet store aquarium, you should still seriously think about whether it is worth getting one. Especially considering the fact that a general fish aquarium is usually not suitable for them.
Sesarma bidens, Pachigrapsus marmoratus, Amarinus lacustris, Limnopilos naiyanetri.
How to keep aquarium crabs at home? 
