Aug 16, 20239 min read

Hermit Crab Emergencies - Flooding & Bug Infestation

Updated: Jul 18

As strange as it sounds, there are situations within a Hermit Crab Tank that are classified as emergencies. And when we say emergencies, we mean they can and will lead to the death of your Hermit Crabs!

The 2 biggest emergencies that can happen within your tank are floods and bug infestations. Both situations should be dealt with immediately.

Flooding

When we say flooding, we don't mean your entire tank is swimming in water. When a flood occurs in a Hermit Crab tank, majority of the time, you won't even know it has happened. Water will pool at the bottom of the tank, at the bottom of the substrate.

To check for floods, simply push a straw directly into the substrate, all the way to the bottom of the tank, up against the glass. Remove the straw and a straw tunnel should be visible up against the glass, check this regularly to see if water has pooled at the bottom of the tunnel. If you notice water pooling, unfortunately, you have a flood.

What causes flooding?

Spraying/Misting water into the tank - You should never spray or mist your tank; you may think it is just a small amount of water and it may make your humidity rise dramatically. However, this is just a temporary fix to humidity issues. Spraying water into the tank regularly will eventually build up in the substrate, and when it has nowhere to go, it will pool at the bottom of the tank, causing a flood.
Leaking pools, overflowing pools - If your pools start to leak, or are too full, they can overflow into the substrate, eventually this will pool at the bottom of your tank.
Bubblers are too strong - Bubblers that are too strong and spray water out of the pools, can eventually lead to flooding.
Too much condensation - Condensation will naturally build up on the glass, but too much condensation will eventually drip down into the substrate and settle at the bottom of the substrate.
Humidity continually too high - Humidity is caused by moisture and heat coming together, but too much humidity can cause to much moisture in the air, which in return can create a wet substrate. Humidity should continually sit between 70-85%.
Coir Peat went into the tank too wet - When adding the substrate and soaking the coir peat, it must be wrung out so that it is damp, not soaking wet. By adding in soaking wet coir peat to your substrate, it will eventually settle on the bottom of the tank.
Pools being knocked over by crabs - If your pools are above the substrate and are not heavy or placed inside a second tub, some larger crabs have been known to tip their pools over.

Signs of a potential flood

Substrate appears wet.
Water pooling at the bottom of the tank.
Months have gone by, and you have not seen a single crab surface.
Pools have been leaking.
Large amounts of water have been spilled in the tank during pool changes.
Pools have been tipped over.

Why is a flood so dangerous?

When water pools at the bottom of your tank, any Hermit Crabs who are moulting can and will drown. They do not have the strength mid moult to save themselves and dig back up. Your moulting crab is currently in an almost hibernated state and does not have the strength to remove themselves from the situation.

If they are left in the flood, they will unfortunately drown.

It is important to try and locate the source of the flood, to prevent it from reoccurring again in the future.

My tank has flooded, what do I do now!?

Don't wait around, as soon as you notice a flood, it's time to take action!

We always say never dig up Hermit Crabs, but during these 2 emergencies, you have no choice but to dig for your crabs, it is a matter of life or death.

Unfortunately, flooding means you will have to completely redo your substrate, that means removing EVERYTHING from your tank, digging out the old substrate and placing new substrate.

Follow the steps listed below.

Set up a temporary tank for your crabs to move to while you fix the flooding situation. Make sure you have isolation tubs ready for any moulting crabs you may find. The most important thing you need in your temporary tank is heat, humidity, water and food. Decor and enrichment are not a priority in this tank, nor is deep substrate. This is only a temporary home for them while you clean out their tank and re do the substrate.
Remove all decor and pools from the tank, as well as any crabs that are currently above the substrate.
Now the digging begins, gently remove substrate from the tank using your hands, you may be tempted to use a scoop or a bucket to dig, but this prevents you feeling a crab that is in the substrate and could possibly injure them. The best way to dig, is with your hands.
Gently remove sand, making sure each handful you remove does not contain a hermit crab. When you do finally come across a hermit crab, and they are not moulting (actively moving when you pick them up, going in and out of their shell) place them into the temporary tank. If you come across a crab that is moulting, use a scoop to gently scoop them up and the sand around them (including their shed exoskeleton) and place them into one of the isolation tubs.
When digging through your tank, make sure you are counting how many crabs you come across. If you know you have 8 crabs in your tank, you need to find 8 crabs. If you happen to find an empty shell, deep beneath the substrate, chances are that, that crab has passed away during moulting and has either been consumed by other crabs or has decomposed.
Once all of the wet substrate has been removed, give the tank a good clean using primed water and a clean rag. Make sure to dry out the bottom of the tank.
When adding your new substrate back into the tank, use the 8 parts sand to 1 part coir peat method. This is also an opportunity to make sure you get your substrate deep enough and to the right consistency and mixture. You can read more about how to set up your tank correctly here https://www.happyhermie.com.au/post/setting-up-a-successful-hermit-crab-tank
Once your tank has been re setup, and your heat and humidity levels have reached the right spot (27-32.c degrees and 70-85% humidity) you can add your crabs back into the tank. The moulting crabs that were placed into isolation, will need to continue their time in isolation until they have completed their moult. You can read more about surface moutling here https://www.happyhermie.com.au/post/surface-moulting-a-hermit-crab-emergency

Prevention

Condensation - Wipe away excess condensation daily if it is building up too much. Alternatively, you can add some dry sphagnum moss along the bottom of the glass to catch any condensation that is dripping down.
Pools - Adding pools onto a second level, doubling up pool containers to prevent leaks, continually checking pools for potential leaks, turning bubblers down to low, adding rocks to the pools to prevent them being tipped over.
Humidity - Keeping your humidity in check, a surge in humidity is nothing to worry about, but months on end of 90%+ is far too high.
Don't Spray/Mist - Never use misting or spraying as a way to gain humidity, it may not lead to a flood straight away, but months and years of spraying will eventually lead to a flood.
Substrate - Making sure to wring out the coir peat when adding it into the tank for substrate.
Straw Test - It never hurts to do the straw test often, even once a month to check for potential floods. As long as you do this directly up against the glass to prevent injuring any moulting crabs.

Bug infestation

The main bug that poses a risk to your crabby crew are ants. They can and will attack moulting crabs, which will often lead to their death. If you find ants in your tank, you will need to do a complete substrate redo.

Follow the steps listed below.

Set up a temporary tank for your crabs to move to while you fix the ant situation. Make sure you have isolation tubs ready for any moulting crabs you may find. The most important thing you need in your temporary tank is heat, humidity, water and food. Decor and enrichment are not a priority in this tank, nor is deep substrate. This is only a temporary home for them while you clean out their tank and re do the substrate.
Remove all decor and pools from the tank, as well as any crabs that are currently above the substrate. Make sure you are not moving any ants into the temporary tank.
Now the digging begins, gently remove substrate from the tank using your hands, you may be tempted to use a scoop or a bucket to dig, but this prevents you feeling a crab that is in the substrate and could possibly injure them. The best way to dig, is with your hands.
Gently remove sand, making sure each handful you remove does not contain a hermit crab. When you do finally come across a hermit crab, and they are not moulting (actively moving when you pick them up, going in and out of their shell) place them into the temporary tank. If you come across a crab that is moulting, use a scoop to gently scoop them up and the sand around them (including their shed exoskeleton) and place them into one of the isolation tubs.
When digging through your tank, make sure you are counting how many crabs you come across. If you know you have 8 crabs in your tank, you need to find 8 crabs. If you happen to find an empty shell, deep beneath the substrate, chances are that, that crab has passed away during moulting and has either been consumed by other crabs or has decomposed.
Once all of the substrate has been removed, give the tank a good clean using primed water and a clean rag. You will need to clean everything that you have taken out of the tank (shells, bowls, pools, decor, wood etc.) to make sure there are no more ants present.
When adding your new substrate back into the tank, use the 8 parts sand to 1 part coir peat method. This is also an opportunity to make sure you get your substrate deep enough and to the right consistency and mixture. You can read more about how to set up your tank correctly here
Once your tank has been re setup, and your heat and humidity levels have reached the right spot (27-32.c degrees and 70-85% humidity) you can add your crabs back into the tank. The moulting crabs that were placed into isolation, will need to continue their time in isolation until they have completed their moult. You can read more about surface moutling here

What causes an ant infestation?

Foods - Leaving fresh foods in the tank for too long, especially sweet foods such as fruit, can lead to ants finding their way into the tank for a feed.
Lid gaps - Gaps within the lid are an open invitation to ants. You should only have a very small gap in the lid for bubbler cords to get out, and for your thermometer/hygrometer cord to go in.

Prevention

Remove fresh foods after 24 hours.
Add Vaseline or liquid hand soap to the top rim of your tank, and to any cords leading into the tank. This will prevent ants climbing up and entering the tank.
Keep your tank off the ground, inside only and away from food storage areas or pet beds etc.
Storing your dried foods in sealed containers.

Other bugs you may find in your tank

Mites - The most common mite you will find in your tank is food mites, these will generally be found in the food bowl, on your dried or fresh foods. They are absolutely tiny in appearance, and pose no threat to your crew, they are only there for a feed. Simply remove the food bowl and give it a good clean and replace with new foods.
Spiders - Although very scary to find in your tank, they do not pose a risk to your crabs, and it is highly unlikely that they will attack a crab. Simply remove them from the tank and take them outside. Do not use any bug sprays in your tank, these can poison your Hermit Crabs.
Springtails - Congratulations, you've got yourself a cleanup crew! These guys can happily live in your tank alongside your crabs. They will help to keep the tank clean.
Cockroaches - Although these can be an alarming site, it is highly unlikely that they will attack your crabs, simply remove all decor and give it a good clean and remove any cockroaches that you can see.
Flies - Flies are not a hazard to your crabs, although they can be difficult to get out of a tank, open the lid and try and encourage them to leave.
Pill Bugs (Roly Poly) - No harm to your crabs and can in fact become a good cleanup crew. You can leave them be or remove them from the tank.

If you do happen to find any sort of bugs inside your tank, never ever spray any form of bug spray into, onto or around the tank. This is toxic to Hermit Crabs and can make them very sick.