Diet

Diving beetles are carnivores, but are not picky in the slightest! In the wild, diving beetles hunt small aquatic insects and crustaceans, with the largest species even eating fish! They will also scavenge any available carrion, as long as the meat isn't too decayed. In captivity, these adaptable hunters will eat any protein-based fish food just as readily! They will also happily eat fresh-killed feeder insects, such as mealworms or crickets, and can hunt aquatic prey such as feeder shrimp, aquatic isopods, and amphipods! 

These beetles do not need to be fed often - a large meal every couple days is more than enough to sustain a group of beetles, and well-fed beetles can go for weeks without any food at all! An excess of food can worsen the water quality and heighten the risk of illness or cloudiness in the water, so it's best to not overfeed!

Housing

Diving beetles vary greatly in size and behavior, so different species may require different tank sizes. For the most part, though, diving beetle species are quite small, and multiple beetles can be kept in a tank as small as a gallon! The largest species like Dytiscus are far too large for a tank of this size, and would likely prefer a tank from five to ten gallons.

Similar to turtles, diving beetles like to occasionally bask and rest out of the water, and so appreciate a small area for this purpose. This could be a small floating piece of wood, a little rocky island, or even something as simple as a stick or plant jutting out of the surface of the water!  The only requirement is that it must be large enough for the beetle to climb onto it!

We highly recommend including plants in your diving beetle tank, which can either be collected outdoors or bought online/at a pet shop! Floating plants and aquatic plants are both very useful in maintaining water quality, and given how hardy diving beetles are, including healthy plants can make the tank nearly maintenance free! Floating plants such as Salvinia and duckweed are often appreciated by the beetles as basking spots, while submersed plants such as Elodea, Ludwigia, Cabomba, and more will serve as both additional structure for the beetles and as decorations for the tank!

Diving beetles will appreciate having structure to both swim through and perch on - these beetles passively float while swimming, and so will try to grab onto submerged objects while resting to counteract this. This can be accomplished in the form of sticks, rocks, plants, or the substrate itself! Including sticks in this manner can sometimes give the aquarium a slight tint, due to the tannic acids leaching from the wood itself. This is harmless for the beetles, and in fact can simulate their natural habitat - in the wild, diving beetles live in bogs and temporary pools of water, which are often heavily tinted due to tannic acids! 

All of the diving beetles that we offer are capable of flight, so we recommend having a lid for their enclosure!

Social Behavior and Tankmates

Although not inherently social animals, many diving beetles live in groups in the wild, and can be kept together in the aquarium! Most diving beetle species are tolerant of one another, so one could plausibly keep a tank with multiple individuals of multiple species! These beetles may occasionally chase one another around, but healthy, well-fed beetles will not fight, and will coexist peacefully. The only exception to this is keeping a diving beetle with a significantly larger species - the largest species of diving beetle may see the smallest species as prey, and as a result would not make good tankmates for one another.

Diving beetles can also be kept with other aquatic beetles, like water scavenger beetles and Haliplids! Although they can often tentatively coexist with animals like water boatmen and backswimmers, these are also very common prey animals for the diving beetles, and as a result should not be kept together unless the diving beetles are kept very well-fed! Snails and caddisflies are also somewhat vulnerable but can often coexist peacefully with diving beetles, acting as cleanup crews for their messy neighbors.

We do not recommend keeping diving beetles with fish! Although some beetles can coexist with fish, diving beetles have a very powerful bite, and can injure or even hunt fish tankmates!