Gorgers of the greenery


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Will your fish leave your tank plants alone? Not all of them says Nathan Hill, as he points an accusing finger at the culprits.

They’re the kind of fish to drive an aquascaper to murder. For the unwary they’ll turn lush growth into stalks in hours. For the wise, they’re the wild card you can’t risk with even the firmest Anubias.

These are the plant destroyers — veg-incompatible fish that are well known, well documented and often well avoided.

It’s not as though we can blame them for their behaviour. That would be like blaming cows for eating grass. However, we can at least familiarise ourselves with the worst of the culprits:

The worst...

Some of the most notorious plant plunderers are those herbivores that thrive on a chlorophyll-heavy diet. They include…

Goldfish: This has a bovine-scale appetite for greenery. Although omnivorous, it will happily munch its way through any vegetation offered. It’ll even try to eat plastic plants.

Silver dollar and close relatives:  A distant relation to the piranha, dollars know exactly how to use their sharp incisors and aren’t fussy about which plants they munch. Big, small, soft or leathery, they’ll happily strip back all types of foliage.

Distichodus: Not a mistake for newcomers as they’re big and pricey, but for the keeper with a larger tank, this attractive African genus will turn a biotope into a barren wasteland.

African cichlids: If it’s from Lake Malawi, it’s a bad idea to house it with plants. Malawian mbuna relish greenery, many adapting to graze on algae, so when a more abundant source appears that doesn’t involve rasping rocks, they’ll take it.

Subtle villains

Some fish are less direct in the way they damage plants, but can still cause problems.

Plecs: The loricariids are a huge group, but only some feast directly on plants. Some, like Otocinclus, actually help to remove algae from leaves. Others, like the huge Glyptopterichthys, tend to be blamed for 'eating' plants, when only uprooting them in bolshie fashion.

Silver shark: Many love the sharks, but when your back’s turned they might make a meal of your soft or fine leaves. They don’t go for broader leaves until they get older, but youngsters will happily nibble at finely fronded Cabomba or mow through Glossostigma.

Tetra: Surprised? Some are terrible plant munchers! Buenos Aires tetra make short work of Vallisneria and even smaller species, like the Red eyes, and even Rummynoses have been seen filling up on ripe, delicate shoots.

Siamese algae eaters: Crossocheilus are often touted as great controllers of fine algae, especially on the leaves of larger plants. However, when not cleaning off Echinodorus, they’ll work their way through cherished mosses and enjoy an expensive buffet.

Clown loach: This is a fish that often leaves the owner floundering because it will never eat plants during daytime. It looks so innocent that the aquarist will blame every other fish, when in reality Clowns love grazing when the lights go out.

Central American cichlids: Ever seen lush growth in a tank of Convicts? Many Central Americans take delight in uprooting greenery. These predominantly insectivorous/piscivorous fish won’t always make a meal of stray plants, but will move them out of the way.

Dwarf gourami: Dwarf gouramis don’t eat plants, but put them to good use, as do many other gouramis and even a few catfish. Gouramis are bubblenesters that make a floating raft under which to lay their eggs. They’re not fussed about construction materials however, being happy to tear apart your frondy plants and gel them together with sticky bubbles.

The innocent, but accused

Shrimps and snails are often implicated, but almost always something else has made a meal of your latest additions.

Snails will indeed eat plant matter, but not when it’s fresh and healthy. All of that tough-to-digest cellulose is hard on their guts and they’d rather have a belly full of something easier going.

Snails savage already dying plants. Once its degrading they’ll soften it into a nutritious slush.

The same goes for shrimps. Some associate damage in leaves with their constant padding action, but in reality the shrimps are picking out any dying flesh — like maggots in a wound.

Seeing snails or shrimps 'eating' plants suggests they’re already struggling with another problem, be that nutrients, lighting or CO2. Snails and shrimps just clean up the mess.

The thin green line

For some fish it doesn’t matter what you add — it’ll be eaten. Others can be thwarted by your defences:

Foul tasting plants: The Onion plant (Crinum thaianum) and Lizard plants (Saururus cernuus) have a bitter taste that fish will nibble once, but never again. However, fish that uproot plants don’t care how they taste, in which case try…

Firmly anchored plants: With cichlids and other fish that uplift greenery, consider plant species tied to wood or rocks, like Anubias or Java ferns. Although they get battered from being tugged and are slow to recover, they are incredibly robust.

Fake plants: Some believe it’s defeatist to resort to artificial plants, but it’s perfectly respectable. In fact, some of the best aquascapes we’ve seen in recent years have been created with nothing but synthetic plants.

Don’t starve me!

If opting to have herbivorous fish without plants, you’ll need to plug this nutritional void. If keeping Silver dollars in a bare tank, just make sure you offer them plenty of dandelion leaf, spinach and other green supplements.

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