Arowana-proof snails… almost

When I started this tank, I added Nerite snails as part of the algae crew. The was some concerns that they will end up as Arowana snacks as I’ve seen my previous Arowana chomping on something and saw what I thought was snail shell fragments dropping from its mouth. Still I decided to try out the Nerites as they are somewhat larger then the pest snails in my previous tank and have much ticket shells. Unfortunately, I never got to find out as the snails died before the Arowana was introduced. Thinking that my tank conditions were not suitable for snails, I never got new snails till now.

Septaria porcellana
Septaria porcellana (Abalone snail) – one of many in GC’s display tanks.

During a  visit to Green Chapter (GC) about a week and a half ago, I noticed that had a new species of snails in their display tanks. They had flat shells, like half a clam. That really got my interest as this would mean the Arowana, if it wanted to, would have a really hard time trying to grab them.

I asked Ron, GC’s ever friendly Dept. of Customer Delight representative, about the snails. He gleefully gushed how they have completed cleaned the glass of the tanks and… this is the best part… showed me how, at the slightest disturbance, they would lockdown and were almost impossible to move by hand. Perfect! The means that it is near impossible for the Arowana to grab them… or so I thought.

So, I got 5 to test in my tank.

These are Septaria porcellana (common name: Abalone snail). So far, they have done a pretty decent job of cleaning algae. The first photo below shows my rocks with half the brownish algae eaten up. The next photo shows the same rocks almost completely clean 2 days later.

Rocks half cleaned by Septaria porcellana
Before
Rocks cleaned by Septaria porcellana
After (2 days later)

They seem to be nocturnal in my tank. I do not seen much of them when my tank lights are on, but the next day they would have eaten some more of the algae on the rocks. They also seem to prefer to be near or buried in the substrate. When I do find them, they are mostly buried in the substrate.

Septaria porcellana half burrowed into the substrate.
Septaria porcellana half burrowed into the substrate.

They seem to be nocturnal in my tank. I do not seen much of them when my tank lights are on, but the next day they would have eaten some more of the algae on the rocks. They also seem to prefer to be near or buried in the substrate. When I do find them, they are mostly buried in the substrate.

At GC, they were all over the tank glass even though the tank lights were on. Maybe they had to ventured out to find more algae to eat.

Septaria porcellana shell fragments
Septaria porcellana shell fragment

Unfortunately, they are not as Arowana proof as I thought. On day 3, my wife noticed some violent movement in the tank in her peripheral vision. She looked up only to see the Arowana chomping on something. She could hear crunching sounds and saw a few slivers drop out. The slivers were too small  to identify in tank, so had to wait for me to fish them out when I got home. And they turned out to be shell fragments of the Septaria porcellana. Sigh! Is there any algae crew that this hungry monster won’t/can’t eat?

Not sure what happened. Did the Arowana get lucky and did a quick enough snatch? Maybe the snail was on a soft surface, like a leaf or on the substrate? Or maybe it was on an uneven surface? Haven’t figured it out yet. At this point in time, I think I still have 3 left. We have confirmed 2 visually. I think 3 because of the 2 confirmed, 1 is working on the front glass, and the other is working on one of the rocks. I think the 3rd is working on the other rock. The 4th and 5th was last seen working on the back glass, but they’re now hidden behind the plants back there, if either are still alive. So which of the unconfirmed got eaten?

If the remaining ones do not die from the water conditions in another week or two, I’ll get another 15 or 20 more and hopefully they’ll help me clean the glass like the GC ones.