How to care for it
Five things keep a crab paludarium healthy.
Water: keep the pool clean
Top up evaporation with dechlorinated water, and change about 10-20% every week or two once it's established. Clean water is what keeps your crabs healthy. Tap water straight from the pipe contains chlorine that harms them, so always treat it first. We use APT Pure to dechlorinate. For a new tank, change water every other day for the first two weeks.
Humidity & air: keep it muggy
Crabs breathe through gills and need humid air and a dry spot to climb out onto. Keep the lid on to hold humidity, and give it a light mist if the land looks dry. A small gap for airflow stops it going stale.
Light: gentle and steady
Give it bright, indirect light or a small LED for 8-10 hours a day to keep the plants growing. Keep it out of direct sun: direct sunlight will overheat any tank.
Feeding: little and varied
Crabs are omnivores. Offer small amounts a few times a week: blanched veg, a little fish or crab food (we feed Hikari Crab Cuisine), and the occasional protein. Remove anything uneaten the next day so it doesn't foul the water.
Temperature: room temperature
Normal indoor temperature suits them. Keep it off direct air-con draughts and away from heat or direct sun.
What's normal at first
A new paludarium is finding its feet, so don't worry if you see:
Frequent problems you might face
Pump making a weird noise: almost always air or a low water level. Top the water up, and gently tap or re-seat the pump to clear trapped air. If it rattles, check nothing's lodged in the intake.
Cloudy or smelly water: usually overfeeding. Remove uneaten food, feed less, and do a small water change.
White, fuzzy mould on wood or land: normal on new wood and rock. Wipe it off and add a few springtails (tiny janitor bugs that eat mould) and they'll clear it for good.
Plant melt or yellowing leaves: some plants drop leaves while adjusting. Trim the mushy or yellow bits; new growth follows.
An escapee: crabs are climbers. Keep the lid on and close any gaps around cables.
Good to know
How do I know when it's cycled and safe for the crabs?+
Give it about 2-3 weeks, then confirm with a water test rather than the calendar. When ammonia and nitrite both read 0 (with a little nitrate showing), the beneficial bacteria are established and it's safe. A simple test kit is the most reliable way to tell. Adding crabs too early exposes them to toxic ammonia. If your build came home already set up, ask us where it is in the cycle.
What can live with vampire crabs?+
In a nano paludarium they do best species-only or with a few snails. Avoid fish: the water is shallow and crabs can be territorial.
How often should I change the water?+
Once established, change about 10-20% of the pool water every week or two with dechlorinated, temperature-matched water. Top up evaporation in between.
How do I wash the filter without killing the system?+
Rinse the filter media in old tank water you've just removed, never under the tap. Tap water's chlorine kills the beneficial bacteria living in the filter. A gentle squeeze every few weeks is plenty.
Will it attract mosquitoes?+
No. With a lid and gently moving, filtered water there's nowhere for mosquitoes to breed: they need still, open water.
How long will it last?+
Years, with the basics. Vampire crabs typically live around two years; the planted system itself is long-term with light upkeep.