Trimming Colomesus teeth

I’m often asked about the best way to keep the teeth of South American pufferfish from overgrowing. The short answer is that there’s no 100% reliable way to keep them from becoming overgrown, though in my experience when kept in a sandy aquarium with an abundance of Melanoides livebearing snails their teeth certainly grow much more slowly.

Part of the problem is that these puffers don’t show much enthusiasm for snails if provided with other foods, such as bloodworms. Making them hungry before adding the snails helps: I like to use crunchy foods like snails or krill first thing in morning, when they’re usually ravenous. One crunchy food they do enjoy is the humble woodlouse, easily obtained from the back garden where it can be found in damp crevices and under pots. Just make sure they haven’t been sprayed with any pesticides.

If the teeth get so long that the beak cannot be opened properly, the puffer is at risk of starving. Trimming the beak is fairly straightforward but can seem very scary if you’ve never done it before. I’d recommend doing a dry run first, sedating the pufferfish and then returning it to the aquarium without actually cutting the teeth. This will give you a chance to get the hang of handling and sedating the fish without having to learn the cutting the process as well!

You will need clove oil (also called eugenol) and cuticle clippers, both available from chemists/drugstores. Take care not to overdose the clove oil; what it does is slow down the nervous system, including breathing, and if you use too much the fish will suffocate and die. You actually need a lot for that to happen, and also need to expose the fish to the stuff for more than a minute or so, and consequently the actual risk is very small, but be careful anyway.

Here’s the process, step by step:

1) Put 2-4 drops of clove oil into a 1-litre tub of water, and stir well

2) Catch your pufferfish in a soft net

3) Gently place the puffer into the tub of water

4) Wait for the pufferfish to settle down; this usually takes about a minute

5) Make sure your hands are completely wet

6) Grasp the puffer gently but firmly, taking care not to sqeeze it too hard

7) The puffer should be quite relaxed; if it ‘puffs up’ then the sedative needs longer to work and you should leave the fish in the water for another 30-60 seconds

8) Hold the pufferfish upside down, and use the cuticle clippers to trim off the points from the teeth in the upper jaw

9) Turn the puffer over and trim the teeth in the lower jaw if required (for some reason these don’t grow as fast); trimming the teeth should only take a few seconds

10) Place the puffer back in the net and then place the net in the aquarium, preferably near the filter outflow or an airstone; after a minute or so the pufferfish should be breathing and moving about normally, and you can release him from the net into the aquarium

Colomesus asellus netted and ready to go

Cuticle clippers and clove oil