Feeding Damage to Aquarium Plants

Posted by on Jul 8, 2011 in All Categories, Problems and Worst Cases | 0 comments

Feeding Damage to Aquarium Plants

Damage to Aquarium Plants - Perforated Leaves and Other Foraging

When Useful Creatures Become Pests: Every once in a while customers call in with questions about plants developing holes or transparent areas. Obviously, this may be caused by a number of things, including nutrient deficiency or adverse water conditions. Quite often, the cause for plant damage is foraging by animals. Invertebrates such as Caridina multidentata or “Amano Shrimp” can cause damage, as can some fish. Particularly, some Bristlenose Catfish (Ancistrus spec.) and adult Siamese Algae Eaters Crossocheilus reticulatus are amongst the usual suspects. Each of these have their own Modus Operandi: Feeding damage has typical characteristics and is also typical for certain plants as not every plant is welcome as part of the diet.

Damage by Caridina multidentata (Amano Shrimp)

Amano Shrimp are a standard in most planted tanks now because they keep algae at bay and are amongst the most undemanding invertebrates anyone can wish for. To get the desired (i.e. algae-reducing) effect, you need a certain amount of these shrimp. With too few of them, too little is achieved.

However, the opposite applies just as much. If you put too many in your tank, your plants may suffer. A well-known principle of toxicology can be transferred to these shrimp: The dose makes the poison.

The rule of thumb is one shrimp per 7 l (1.8G) of water. With a higher shrimp density, there will eventually be too few algae to feed the shrimp. Consequently, other sources will be explored. Hungry shrimp eat everything. Even healthy plants.

Garnelenfraß bei Limnophila spec. "Vietnam"

Shrimp feeding damage in Limnophila spec. "Vietnam"

There is one exception to this rule: If Hemianthus callitrichoides “Cuba” is present, the shrimp density should be halved. Especially during the establishing phase, this plant is susceptible to complete eradication by the Amanos.

To complicate things further, there is one more exception. Fine-leaved Rotala species will be eaten even when there are enough algae to go round. Do not keep more than one Amano Shrimp per 25 liters (6.6G) of water or opt for a different algae eater altogether if you want to keep these plants. You will easily recognize shrimp damage to Rotalas by completely bare stems with all the whorls of leaves gone.

Bristlenose Catfish (Ancistrus spec.) Feeding Damage

Sometimes, the feeding occurs overnight, after the Ancistrus discover their taste for a particular plant and grate away at the leaves, creating holes with patches of damaged tissue.

Fraßschaden an Echinodorus

Feeding Damage in Echinodorus

It may be a while until this happens, with both the Ancistrus and the plants present – sometimes they co-exist for weeks or months with no traces of plant damage. Sometimes, a plant is attacked directly after planting, as a new plant is perhaps more easily noticed by the fish.

Fraßschaden an Alternanthera

Feeding damage in Alternanthera

Damage by Adult Crossocheilus Algae Eaters

My own experience with this Genus of algae eaters is limited to Crossocheilus reticulatus. This species, like most algae eaters in that genus, is herbivorous when young but will develop a more omnivorous appetite as it matures. This means, their preference for algae diminishes over time. By the same token, more protein-rich food as well as higher plants appear on the menu.

Fischfraß bei Limnophila aromaticoides

Light Fish Foraging in Limnophila aromaticoides

Feeding damage caused by Crossocheilus is recognized by clipped leaf tips. Preferred source are stem plants, again with Rotala species at the top of the list, but also Helanthium tennellum and other more delicate species.

The Limnophila shown here has only been damaged lightly with some leaf tips missing. Courtesy of two adult C. reticulatus in 800l (211G) of Water.

Copyright of images:

Image 1&4: Stephan Mönninghoff
Image 2: Dominic Degel
Image 3: Patrick Weinhold

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