How to care for your new Nerite Snails, Nerita species (probably Neritina natalensis) with pictures

Introduction. I first found out about these snails by accident. They look like juvie variations of mystery or trapdoor snails so I took no note of them. Then I would see tiny white eggs in some tanks. They were randomly distributed, very hard, and smaller than a sesame seed -- even smaller than a pin head. They never hatched. They just stayed there on the glass until I wiped them off (actually scraped them off with a razor blade). It wasn't till years later that I found out exactly where those eggs came from.

Description. Part of the reason nerite scales remained below my snail radar for years is their small size. They're under an inch. Larger than the Physa pond snails which you always notice because they overrun most fish tanks they wander into as hitchhikers on aquarium plants. That's probably where my first nerites came from (before I ever heard of them). Non-descript fits them quite well. They are nice looking if you get close enough to notice them. You'll see some variations in color -- some browns, some blacks, even olive. Colors that enable them to lay low on the horizon.

On Your Front Glass. Nerite snails show up much better on your front glass. Most of them prefer to maintain a much lower profile. They don't actually hide per se, they just wind up in less visible areas. You may have one or two in your tank and never even know it. I had to find several of these show up before identifying them. I like snails but I'm certainly no molluscologist (and I can prove it).

Lots of Nerites in Saltwater. Nerite snails appear in many areas of the ocean. They come in many colors and shapes. They make excellent algae eaters. They are widespread and also grow in brackish and freshwater strains (species, variations, or whatever). The brackish and freshwater strains appear to adapt to both types of waters.

Re-Introduction. As I learned more about nerite snails, I kept my eyes open for their commercial availability. When I spotted them on one of my wholesale lists, I invested a huge sum in ten of them (actually, they retail for $2). So they're not expensive. They're just hard to find. I put them in an algaefyed tank and forgot them for a couple of weeks. They just sort of disappeared in a mostly bare 10-gallon tank ocupado with a piece of driftwood, a sponge filter, two red lizard catfish (really two brown males), four flower shrimp, and the 10 nerite snails. None of the living critters in there believed in displaying. When all the algae was digested, the nerite snails re-captured my attention.

LA
10 nerite snails were in this 4-inch bowl 10 minutes ago. They're not big. They scoot right along.

Escapers and Eaters. You'll note a couple of facts from the picture above. #1. One of them climbed out seeking greener (from algae?) pastures. None of them escaped from their former algaefyed 10-gallon ranch -- probably because they had plenty of grazing pasture. The absence of food made them start to wander. #2. Within the 10-minutes they were in their 4-inch arena, they left a great deal of digested algae. Nerite snails have justly earned their algae-eating rep.

LA
Back in a new 10-gallon algaefyed tank, they bail rapidly from their 4-inch corral.

No Protective Flap. Nerite snails possess no protective flap to keep them from drying out if they wander from their watery home on the range. We've all had mystery snails intent on laying their eggs above water level climb out and fall to the floor. We find them on the floor a couple days later, we toss them in the water, and they manage to survive. If a nerite snail climbs out, he will likely dry and die. Oddly enough, land snails have no flap either and they quickly secrete a mucous seal that keeps them from drying out until the next rain. I haven't had nerites long enough to know if they have this survival skill. (Added later: They clamp to the surface very tightly to prevent dessication.)

On Their Backs. Nerite snails remind me of sulcata tortoise when they land on their backs. This only happens when you drop them in the water. They do not wind up on their backs during their normal activities. Dropped nerites struggle quite a bit to right themselves.

Breeding Nerite Snails? You'll see plenty of eggs from your nerite snails. Evidently they come in males and females. No way can I tell the difference. As mentioned way back at the beginning of this tome (which is proceeding at a snail's pace), their eggs are white and slightly smaller than the head of a straight pin. No way will they hatch in this planted tank. It's owner, Matt Helgeson, adds carbon dioxide to get this lush plant growth. He adds the nerite snails to help control algae. The CO₂ lowers the pH, which makes the plants grow but tends to dissolve snail shells.

LA
Carbon dioxide in the water creates carbonic acid which dissolves snail shells. He's 0.5-inches long.

LA
10-gallon tank with a fine layer of algae on the sides and bottom, plus 10 nerite snails.

LA
So we "fed them" a red algae infested African water fern. They pretty much ignored the red algae.

Hatching their Eggs. Nerite snails breed in whatever water they find themselves in. However, their eggs hatch only in brackish water. S0 ... Mine will be going into a brackish water tank just as soon as they polish off the algae in the above aquarium.

Utilitarian Snails. This tank sits in a window with a southern exposure -- a near perfect home for algae growth, especially with the carbon dioxide injections. The nerite snails are excellent algae eaters. They do not eat plants.

Last Words (temporarily). We'll report at a later date on whether the nerite snail eggs hatch in our brackish water. LA (Later date: They did not hatch. None of their eggs have ever hatched. LA)

Lisa Steinberger, Phillipsburg, NJ, December 20, 2009
Hello! I love your website, it is extremely helpful, and often humorous as well. I have a planted goldfish tank that developed the initial diatoms at startup, so I decided to add some olive nerite snails. They are totally AMAZING!!! They've cleaned the entire tank to brand new in less than a week. WOW!!

So that brings me to some questions about something shared by these particular goldfish (pearlscales) as well as the snails---both are recommended to have calcium in the water (to make the hardened pearl scales on the goldfish, and to make sure there is sufficient calcium to keep the snail shells healthy). So how does one test the water for calcium? and what ranges are acceptable? And how does one add calcium if insufficient? Thank you so much!!!

I live in Phillipsburg, NJ which has 'liquid rock' as water, all my glassware etc. has the white coating left behind on it, which was one of the main reasons for choosing goldfish which I seem to love (the pearlscales especially). But truly I haven't been able to find clear instructions. Thanks again!!

A: You can find Calcium Test Kits at your local fish store, but you probably don't need one -- especially as there's no specific Ca level you're shooting for. And it sounds like you already enjoy more calcium than you need as evidenced by the white precipitate on your glassware and the very fast growth of your diatoms. If you still think you need more, add a cup of crushed coral. LA

LA
Eight nerite snails added to this tank December 30, 2009. Also added a half cup of salt to hatch their eggs.