Sometimes referred to as “the chicken of the sea,” due to its delicate taste and versatility, tuna is a saltwater fish that belongs to the mackerel family. Tuna is a staple of many pantries and can also be offered to hermit crabs, with certain caveats.
Hermit crabs are naturally omnivorous, so they’ll enjoy eating fish. Tuna is beneficial to hermit crabs, especially when offered fresh. Tuna can be fed to hermit crabs raw or cooked, providing much-needed protein (amino acids) for the hermit crab’s exoskeleton, alongside other health benefits.
Unfortunately, tuna consumption does have drawbacks, especially when canned. All tuna contains mercury (a heavy metal), the consumption of which must be strictly limited. Tinned tuna is also often high in salt (sodium) and could be preserved with brine, which contains toxic additives.
Do Hermit Crabs Like Tuna?
Place a small tuna dish in a hermit crab’s tank at dinner time, and you’ll likely witness a feeding frenzy when hermit crabs awaken in the late evening.
Hermit crabs are attracted to food by scent, detected by their antennae. The strong smell of fish will be familiar and pique the interest.
Is Tuna Good for Hermit Crabs?
Having established that hermit crabs enjoy the taste and scent of tuna, we must assess its safety. While hermit crabs eat tuna fish, suitability is conditional.
When people ask, “is tuna bad for hermit crabs?” they’re likely questioning tinned tuna. Most fresh fish is safe for hermit crabs, as long as it’s prepared appropriately and served in moderation.
Tuna fish is a good addition to a hermit crab’s diet. It’s not something to feed daily, but it’s a rich source of protein. However, the presence of mercury in tuna must be considered.
Advantages of Giving Tuna to Hermit Crabs
Aside from hermit crabs finding tuna familiar and comforting, there are various health benefits.
Tuna fish is an excellent source of protein for hermit crabs, aiding their physical growth and development and providing Vitamin D for calcium absorption, which is essential for the exoskeleton.
Tuna fish contains omega-3 fatty acids. We commonly associate these with human cognitive function, but these healthy fats promote bright and vibrant skin coloring in hermit crabs.
Disadvantages of Feeding Tuna to Hermit Crabs
There are two significant hazards when feeding tuna fish to hermit crabs: sodium and mercury.
Mercury is a heavy metal in all saltwater fish, although it’s most commonly associated with tuna. Located in the ocean, mercury is absorbed by algae and cycles through the food chain.
A small creature, like a shrimp, will eat the algae, then a tuna fish will eat the shrimp. The larger the tuna, the more food containing mercury it’ll consume, creating a build-up over time. Once a hermit crab eats the tuna fish, it, in turn, consumes mercury.
If overeaten, tuna will lead to fatal mercury poisoning. Fresh tuna contains more mercury than canned, and Environmental Research explains that light tuna, such as skipjack, contains the least mercury.
The sodium content in tinned tuna can be fatal. If you wish to feed canned tuna to your hermit crabs, always look for a brand that doesn’t contain added salt.
How To Give Tuna To Hermit Crabs
Before offering tuna fish to hermit crabs, you must understand the different types:
- Yellowfin Tuna,
- Ahi Tuna (Big Eye Tuna)
- Skipjack Tuna
- White Albacore Tuna
Of these fish, always look for a smaller, lighter tuna fish to feed your hermit crabs.
Skipjack is the safest to manage the risk of mercury.
Fresh Tuna
Fresh tuna is better for hermit crabs than tinned. By getting fresh tuna, you won’t be exposing your hermit crabs to the hazardous ingredients found in brine.
Serving fresh tuna to hermit crabs is more work. Assuming the scales are small, you won’t need to descale the fish. However, you must debone the fish if that hasn’t already been done, as the small bones of a tuna are a choking hazard for hermit crabs.
Fresh tuna can be offered to hermit crabs raw or cooked. Just cut the tuna into bite-sized chunks. Hermit crabs don’t have teeth, and can only carry so much in their chelipeds, so dice the fish into small pieces.
If preparing fresh tuna seems too much work, consider tuna steaks as an alternative. These can be cut down to size and served accordingly.
Tinned Tuna
There are multiple types of canned tuna, offering varying levels of safety for hermit crabs.
While tinned tuna usually contains less mercury than fresh tuna, different concerns still need to be addressed. Choose your tinned tuna carefully if you plan to share.
Tuna in Spring Water
If you’re going to offer your hermit crabs canned tuna, make it one that’s surrounded by spring water. This minimizes the risk of harm to hermit crabs, as it doesn’t contain additives.
Tuna in Oil
Most commonly, you’ll see tuna in sunflower oil or tuna in olive oil. These cans will be cheaper than spring water tuna but shouldn’t be offered to hermit crabs.
Sodium and additives are a major concern when offering canned tuna to hermit crabs.
Tuna in Tomato Sauce
Hermit crabs can eat tuna fish and tomatoes, but they shouldn’t eat tuna in tomato sauce. A canned tuna surrounded by tomato sauce is likely high in additives and preservatives.
Aside from sodium, tuna in tomato sauce contains sugar.
Can I Feed My Hermit Crabs Tuna Every Day?
Only offer tuna as an occasional treat once per week. When your hermit crabs aren’t eating tuna, identify another food source that’s a good source of amino acids.
You could try salmon, as this will also supply hermit crabs with essential omega-3 fatty acids, although hermit crabs may reject fish twice in a row. Hermit crabs like to eat various foods, so they often ignore foods they’ve consumed in the last 24 hours.
There are plenty of reasons to introduce tuna fish to a hermit crab’s diet. Offering hermit crabs fish will remind them of their wild origins, and tuna has a range of health benefits.
