How to Clean Texas Holey Rock

Texas holey rock (or honeycomb limestone) is a great aquarium addition for many hard water species of fish, especially African Rift lake cichlids. It’s filled with caves, holes, and crevices all around to create many small territories throughout your aquarium, which helps reduce territorial and aggressive behaviour. It also has the benefit of leaching its minerals into the water, raising alkalinity and keeping the pH stable.

Texas holey rock does have a downfall though, it’s quite the pain to clean. The real stuff is ridiculously heavy, and all the small nooks and crannies throughout holey rock allow a space for plenty of dirt and crud to call home. If you just picked up a new piece of holey rock, it’s really tough to pinpoint exactly what all that crud is. The only thing we know for sure is that it’s best if it isn’t introduced to your aquarium. If it is, it could result in a parasitic infestation, illness, or death of your fish.

It’s not only before you add new holey rock to your aquarium that you need to worry about cleaning it though. Over time, plenty of uneaten food, debris, and fish waste can collect in these small areas while it’s in your aquarium, and algae can even start to grow on it. The algae is really just an eyesore to say the least, but the uneaten food, debris, and fish waste can cause significant problems as far as water chemistry goes. If it’s left for too long, it can produce ammonia. With an increase in ammonia production, your aquarium’s beneficial bacteria may not be large enough in numbers to convert it all to nitrite and nitrate (something known as the nitrogen cycle). In such a situation, you could really harm your fish.

To help you guys out a little bit, below we’ve listed five steps that explain how to clean Texas holey rock. These steps will apply to you if you’ve just purchased your holey rock and are doing the initial cleaning before adding it to your tank, or if you have had it in your aquarium for a while already and it needs a cleaning. That’s enough chit-chat though, let’s get started.

Step 1

Pressure Wash

Pressure washing is a great start to cleaning Texas holey rock. If you don’t have one to call your own, just take your rock to the closest car wash that does and spray the heck out of it. You want to make sure to spray every inch of it. Even shove the nozzle of the pressure washer into the openings of the holes on the holey rock to spray out all the dirt and crud. After it’s all done, you may notice that your holey rock looks a little brighter already.

Step 2

Bleach & Scrub

After you’re done with the pressure washer, the next step is to bleach a scrub the holey rock. This step will disinfect and remove anything that you may have missed with the pressure washer.

The first thing you want to do is place the holey rock into a bucket, then pour in some bleach. Add enough hot water to the bucket to produce about a 10% bleach solution in the bucket. Then put on some protective gloves, grab a tough bristle scrubber, and start scrubbing away. Scrub as much as you can and feel free to use an un-used toothbrush to get into the areas you can’t reach with the main brush.

After you’ve wiped down the whole thing, let the holey rock sit in the bucket of bleach and water for a while. The general idea here is that the longer you wait, the better. But we typically recommend to leave it for about a day or two.

Step 3

Rinse, Rinse, & Rinse

Now that you have pressure washed, bleached, and scrubbed your Texas holey rock, it should now be free of almost all the contaminants, crud, and discoloration. The next step is to remove any bleach residue from the rock. You see, most bleach products are chlorine-based. Chlorine has the nasty habit of destroying the oh-so-valuable bacteria our aquariums house to convert ammonia and nitrite into nitrate during the nitrogen cycle. Therefore, if we didn’t remove any of the bleach residue before putting the holey rock into our tanks, the concentration of ammonia and nitrite would increase to toxic levels. As mentioned before, this scenario can cause your fish some serious harm.

To remove the bleach residue from the rock, simply pour out all of the bleach solution that you had in the bucket, and rinse the bucket and the rock under running water. Next, place the holey rock back into the bucket, fill it with fresh water, and add a healthy dose of dechlorinator. The dechlorinator will help destroy the chlorine that is in the bleach residue left behind on the rock and in the bucket.

You want to let the rock soak for quite a while. Again – the longer, the better. But we recommend about a few hours to a full day. At that point, pour out the water and repeat the process with fresh water and dechlorinator again. The more times you do it, the better, but it’s common practice to rinse until you can no longer smell the bleach, then rinse it once more.

Step 4

Sun Dry

Even after all the rising and dechlorinating done in the previous step, chances are, there is still bleach residue on the rock and on the inside lining of the bucket. The most effective next step is to let the Texas holey rock bathe in direct sunlight. The sun should heat up the rock quite a bit and evaporate any moisture that is on its surface. In doing so, the bleach should evaporate with the water, and as an added benefit, the sun should make the rock even brighter in color.

Step 5

Rinse Once More

Once you have completed the previous 4 steps, your Texas holey rock is pretty much clean. Before you go adding the rock into your aquarium though, we recommend giving it one last quick rinse under running water. You never know, some dust could have settled on it while it was sun bathing. We just think it’s better to be a little over-precautious than under.

Dealing with Algae

When your holey rock is in your aquarium for quite a while, especially if your aquarium gets lot of light, algae is bound to form on its surface. You could go through the process of cleaning the holey rock when it starts to bother you every time, but we recommend considering introducing an algae eater to your aquarium. They’ll love the snack, and I guess you could say it’s a little more natural than cleaning it by hand every time.

If you are looking for more ways to combat algae growth, check out this video:


The process of how to clean Texas holey rock is rather straightforward. Throughout this article, we have explained five steps you can follow, but the general idea behind it all is pressure wash, further remove any contaminants with bleach, rinse, then sun dry. After it’s in your tank, an algae eater will certainly help with keeping the holey rock bright and shiny for days to come. But don’t forget to clean it again eventually to remove any collected fish waste, debris, or uneaten food that gets caught in its crevices.