.jpg){kind=link}
Descripción
If you have green algae encrusted on the glass and you are tired of scraping, this is the answer. The zebra nerite is arguably the best algae eater in the freshwater aquarium: it rasps green film and hard algae off glass, rocks and leathery leaves with an efficiency no fish matches, and it does not touch healthy plants.
It reaches about 2.5 cm and shows the pattern of black stripes over gold that gives it its name. But its great advantage is something else, and it is what made it a classic: it cannot reproduce in fresh water. Its larvae need brackish water to develop, so it will never become a pest however many you keep. That is the difference between controlling algae and swapping one problem for another.
There is a minor trade-off worth knowing beforehand: it does lay eggs. Hard white capsules the size of a sesame seed, stuck across every hard surface in the tank, that never hatch. They are unsightly and have to be scraped off by hand. Many people discover this after buying four nerites.
It lives with everything. Entirely peaceful, bothers nobody and is safe with shrimp, even newborn ones. You only need to avoid snail-eating fish such as loaches.
And a practical warning: it escapes. It climbs the glass above the waterline and, without a lid, turns up dried out on the floor. It is one of the commonest causes of death and entirely avoidable.
Hábitat
Neritina natalensis lives in rivers and estuaries along the east African coast, moving between fresh and brackish water depending on its life stage. Adults move upstream into fresh water and larvae drift down to the estuary, a cycle that cannot be completed in an aquarium and which explains why it never breeds at home.
What it does need from the aquarium is hard, alkaline water, and this is the point that kills the most nerites without anyone making the connection.
A snail's shell is calcium carbonate, and in soft or acidic water it dissolves. First whitish patches appear, then the apex turns porous and eventually holes through. The damage is irreversible and, once it reaches the interior, fatal. A nerite in a soft-water Amazon tank has months to live.
If your water is soft and you still want nerites, there is a fix: limestone in the decor, a calcareous substrate or a calcium supplement. And in any case it appreciates hard surfaces to graze: glass, rocks and algae-filmed wood are its larder.