Minimum Tank Size: 10 Gallons (45 Liters)
Care Level: Moderately Hard
Water Conditions: 6.5-8.0 pH and Moderately Hard to Very Hard
Temperature: 68-77 °F (20-25 °C)
Maximum Size: 2 inches (5 cm)
The term Mexican dwarf crayfish is used to encompass several species (Cambarellus) of small, peaceful crayfish. This also includes the relatively new orange dwarf crayfish, which is rapidly becoming one of the more popular species of crayfish to keep.
Dwarf crayfish are native to Mexico and the southern United states. They primarily inhabit streams and small rivers, though they can also be found in ponds and lakes. They tend to prefer slow moving waters, and are mostly found in the shallows.
They remain relatively small in the home aquarium, and the largest species of dwarf crayfish will only grow to about 2 inches (5 cm) in length. On average, they live two to three years in captivity, though there have been recorded instances of them living longer.
Dwarf crayfish are undemanding when it comes to housing, and a handful of them can be housed comfortably in a 10 gallon (45 litre) aquarium. However, if you want to keep more than two or three of them in an aquarium, then you should consider a 20 gallon (91 litre) long aquarium to be the minimum size.
Any aquarium containing dwarf crayfish should include numerous hiding places. Crayfish molt regularly and they require a place to hide until their shell hardens again. Until their shell hardens, they are completely defenseless against other crayfish and fish in their tank – so include hiding places if you don’t want them to get eaten.
You can tell that a crayfish has molted by the fact that the substrate of the tank will be strewn with what looks like crayfish body parts. Don’t panic if you see this, since it’s just likely molted out of its old shell.
When choosing a filter for a dwarf crayfish tank, it’s important to choose a high quality filter. They tend to be more sensitive to water conditions than other crayfish, and they do not handle ammonia or nitrites well. Usually hang on back (HOB) filters make the best choice for dwarf crayfish tanks, though sponge filters can also make a good choice. If you do decide to use an HOB filter, you should cover the filter intake with material to ensure that no crayfish hatchlings are sucked up into it.
Something unique to dwarf crayfish is that they can usually be kept without incident in community fish tanks. They are a relatively non-aggressive species of crayfish, though it should be said that there are exceptions to every rule (they may also prey on small fish like neon tetras). Because of their small size, they should never be kept with large fish, or other large crayfish. If they are kept with either large fish or crayfish, they will quickly become prey.
Mexican dwarf crayfish are omnivores, and they will eat just about anything that they can get their claws on. In the home aquarium, they should be fed a regular diet of a high quality sinking pellet, along with regular feedings of live or frozen foods and vegetables. I recommend feeding them Hikari Algae Wafers, which are perfect for crayfish.
When choosing their live food, make sure that you only select bottom dwelling live food. This can include blackworms, brine shrimp, gammarus, earthworms and snails. Live foods that are top or mid dwelling like mosquito larvae and daphnia will go uneaten.
Dwarf crayfish will also appreciate the regular addition of vegetable matter to their diet, and their favorite vegetables are shelled peas and zucchini and cucumber medallions. All vegetables should be thoroughly cleaned and blanched prior to adding them to an aquarium. They will even accept dried aquarium plant cuttings and leaves, though that can quickly foul your aquarium if you’re not careful.
Breeding dwarf crayfish is relatively easy, and will usually occur with no intervention from the aquarist. The only true requirement for breeding is to make sure that you have at least one male and one female in the tank.
When breeding is initiated, the male pins down the female and deposits sperm near her sperm receptacle. The female will carry the eggs from anywhere between one to four weeks. The length of this is highly dependent on the temperature of the aquarium. After that time, the female will lay between 20-60 eggs while hiding in a cave or underneath an overhang.
The female will then fold her tail under the body, and fertilize the eggs while forming a mucus sack around the eggs to protect them. The female will carry the eggs for four to five weeks, while using her appendages to keep the eggs clean of dirt and well oxygenated.
Once the eggs hatch, the baby crayfish will remain with the mother until they are ready to set off on their own in the aquarium. If you want a high hatchling survival rate, then you should add numerous small hiding places for the baby crayfish.
The hatchlings don’t have any special food requirements, and will often scavenge for food on the aquarium substrate. Just make sure to add food to the tank at several locations, so that the baby crayfish have a chance to get some of the food.