As anyone who has kept plants and fish together know, some species of fish either don’t like plants, or like them too much. So we end up seeing our valuable plants getting uprooted, mangled or eaten. At times even fish that are supposed to be plant-friendly end up being plant hazards. I will cover some of them this month.
Marbled headstander (Abramites hypselonotus). A very interesting fish that swims with its head down, until it decides to dart across the tank when it swims horizontally. Supposedly a limnivore (mud eater) and herbivore that will eat tender plant shoots. Well, never mind the tender shoots, what this fish really likes is to chew the stems of swordplant (Echinodorus) leaves. There are few things as frustrating as finding large Amazon swordplant leaves floating at the surface, with only the tip of the stems chewed up. Not one or two, but half a dozen per day! The young leaves were unharmed. The fish also caused the vals to become ingrown. I would find two or three plants growing on top of each other, with the tip of their leaves chewed up. I believe this fish may be telepathic, for on two occasions that I found a long forgotten plant doing really well, the fish found and dispatched the plant by the next day. Despite all this the headstander was my favorite fish, and the last troublemaker to leave the tank. I gave it away to a good home and it is doing very well.
Siamese algae eater (Crossocheilus siamensis). This fish does an excellent job cleaning the furry types of algae, yet it is gentle enough not to damage tender plants like stargrass (Heteranthera zosterifolia), and it won’t harm the smallest fish in your tank. Get a couple of full grown SAEs determined to get at the frozen brine shrimp that got lodged under the Anubias and you get a new floating plant. These guys ram into the rhizome and push their heads between it and the sand. Gradually the plant gets uprooted and floats. They do uproot very small plants regularly, so grow your little plants in another tank first.
Young Corydoras schwartzi. What damage could these cute little catfish do? Well they pushed the sand from around the Anubias to get at the brine shrimp, prompting the SAEs to start their ramming attacks. The Anubias is fine, and the whole thing was quite fun to watch, particularly since I didn’t know why the plant was not rooting properly.
Bristle-nose pleco (Ancistrus dolichopterus). Excellent algae eater, particularly for the types that have to be scraped. For a while I couldn’t understand the cause of the white patches in my Amazon swordplants. These patches would eventually rot, creating holes in the leaves. Some plants even resembled Madagascar lace plants (Aponogeton madagascariensis). I determined the cause to be a severe case of “ancistrosis”. If you don’t have enough algae in your tank, and there is not enough food left at night when these guys like to roam, the hard-leafed plants make an excellent meal. Wardley Spirulina Disks apparently are not as tasty as Amazon swordplants. I determined that four adult fish and about thirty growing fry were more than my plants count handle. Once I lightened the Ancistrus load the plants recovered. Also, make sure you have some real driftwood in your tank for they love eating wood.
Severum (Heros severus). Now what is a big cichlid doing in a planted tank? According to my books severums are neither plant eaters nor burrowers. But as intelligent as cichlids may be, they don’t read fish books. My severums decimated the vals, ate most of my prized Sagittaria, and chewed up the Amazon swordplants badly. The stargrasses were saved only by shear numbers and growth rate. The severums did a good job on the hair algae too. They seemed to fight with it, ripping it from anything it was attached to. To prove that severums like their veggies I stuck a small head of broccoli in the sand. In no time all of them were noisily crunching the broccoli. There was nothing left of it next day. I never had a problem with them burrowing though.
Smiling acara or curviceps (Laetacara curviceps). This cichlid is plant-safe, except for small plants. Like the severums it doesn’t read books, so it doesn’t know that the crowns of Cryptocoryne, val, and Amazon swordplants are supposed to stay above the substrate. My pair is constantly remodeling the floor of their tank, moving sand here and there and burying all the small plants.
Rainbowfish (Melanotaenia spp.). I have two species Melanotaenia splendida splendida and M. praecox. Both like to nibble on tender leaves and are doing a number on the ludwigias and stargrasses. I confirmed that they eat algae. The M. splendida cleaned up a tuft that developed on a piece of driftwood very near the water surface. The SAEs are surface challenged, so the tuft grew until I added the rainbows. They don’t mess with the harder-leaved plants.
So, with the exception of the severums and the headstander, the fish mentioned here are not at all bad. If we keep fish that may eat plants we must be aware of their dietary needs and cater for them accordingly. Don’t assume they will eat algae and leave the other plants alone. As I found out, even feeding with fish food specially formulated for herbivores is no guarantee the plants will not be touched. A well planted tank with only a couple of well fed possible herbivores shouldn’t have any problems as long as the plants are doing well. On the other hand, what to do when your plants are taking over the tank? Feed them to the herbivores!
Riehl, Rüdiger, & Baensch, Hans A. (1986). Aquarium Atlas. Melle, Germany: MERGUS-Verlag. ?