What Rocks Are Good For Axolotls? (Health and safety matters)

The addition of rocks to your axolotl tank can be really visually appealing and also a source of entertainment and security for the axolotl. But not any rock can be put straight into the aquarium. A good rock needs to be the right size, safe, and the right type.

Read on to find out all the information you need to source and prepare the right rocks for your axolotl, keeping it healthy and safe.

What Rocks Are Good For Axolotls?

Let’s look at a general list of typical rock types that can be found for your axolotl, that are either suitable or should be avoided.

If you are unsure of a rock leave it out of the tank, don’t use it. Remember that if there are any issues with chemicals, elements, or compounds that are no good for your axolotl, the larger the surface area of the rock means the quicker the transfer into the water. That basically means that large rocks that are unsafe can quickly change the water composition, which can be harmful to your axolotl.

There’s no doubt that large rocks in an axolotl tank look pretty cool. But apart from the aesthetics axolotls like large rocks to climb and sit on. The rock will have a good grip and keep your axolotl interested. A good-sized rock also gives your axolotl somewhere to hide behind, if they are sharing their tank and want a bit of privacy.

If the shape of the rocks allows they can be leaned against each other to make a tunnel or hideaway in between them. Although make sure they can’t topple!

Lighting is also a problem for axolotls as they don’t have eyelids. Well-positioned large rocks can give your axolotl the opportunity to keep away from any light source and give some protection to their eyes. One idea is to stack flat different-sized rocks on top of each other to create sheltered ledges.

Large Pebbles Are Not Rocks

Size is important! A large pebble is not a rock.

Anything that is the same size or smaller than the head of your axolotl can be easily swallowed and cause impaction. This is essentially when the object is ingested and causes a serious blockage. Sometimes this can be fatal. Anything like the pebbles shown in this picture are far too small to be safe for your axolotl.

The rocks we are talking about are typically the same size as your axolotl, or bigger. A stand-alone feature.

Some Rocks Should Be Avoided For Your Axolotl

Axolotls have a very delicate slime surface and gill filaments, both of which are easily damaged. So it’s really important that anything put into their tank isn’t going to cause damage. Rocks should be smooth, with no sharp edges or have anywhere on them that can snag.

The composition of the rock is also very important for the pH balance and hardness of the water in your axolotl tank. If the rock contains bicarbonate or carbonate these will leech out into the water changing the balance of the water, increasing hardness and increasing alkalinity.

To test the rock use the nitrate test solution NO₃ No.1 in your water testing kit, as the solution contains hydrochloric acid. Put a couple of drops of the solution on the rock. If the solution starts to fizz and bubble then the rock contains bicarbonate or carbonate. For your axolotl only use rocks that are not reacting to the nitrate test.

Sourcing The Right Rocks For Your Axolotl

There are several places you can source good rocks for your axolotl tank.

Location	Cost	Quality
Pet Store	$3.50-$4.50 per lb	Excellent
Landscaping Supplier	$0.20-$0.50 per lb	Excellent
Freely Sourced	free (or agreed payment with owner)	Poor to Excellent

The most obvious place to start looking for rocks is at the local pet store. But be warned this is supply and demand and it’s common for these stores to charge a premium price of anywhere around $3.50 to $4.50 or even more per pound of rock. Rock is heavy, so if you are looking for several pieces the cost can escalate dramatically.

The next option for some good rocks that will suit your axolotl tank is thinking outside the box and coming up with alternative suppliers. Landscapers use rocks in their designs, so finding their suppliers is a good option. You’ll find those rocks are only going to cost cents per pound, probably 80-90% less than at the pet store. Another good place to look for rocks is a garden supplies store.

Then there is free! That’s going out and freely choosing your own rocks. There are a few things to be very careful with when doing this.

• It can be illegal to remove rocks in some places, so check local ownership and laws
• Make sure you don’t source rocks near any possible pollution or you’ll likely poison your axolotl
• Check the type of rock and its composition

For all rocks, it’s important that they are free from debris, organic matter, and bacteria before placing them with your axolotl. If organic matter is left on the rocks it could decay and cause a spike in ammonia. The simplest way to do this is to soak them for 30 mins in water containing a bleaching solution, thoroughly brush and rinse off.

Then place the rocks in a low oven for about 30 mins. It’s important to not heat the rocks too quickly as they can fracture and pop if there is moisture inside that can’t escape quickly enough.

The heat is enough to ensure there are no living organisms left. Once the rocks have cooled down they are ready to be introduced to your axolotl.

Axolotl Enrichment and Variation

Rocks can be a great source of fun and enrichment for your axolotl. It can be a really good experience for your axolotl to occasionally move their rocks around or swap out with completely different rocks. It just gives them a new experience in their tank, which is important for their wellbeing.