Gabor Horvath recounts his love for three very different suckermouths. Could you be tempted by one from this gorgeous triad?
IMAGINE YOU’RE SHOWING your aquarium to guests, pointing out your rare, expensive, or colourful species. While explaining you suddenly realise that they’re not following you, as their attention is focused on a fish that has just unexpectedly (to them) attached itself to the front glass. Sound familiar? For some reason ‘sucker’ fish species have a tendency to steal the limelight from their brighter and more active tankmates.
I find them fascinating, too, and can spend hours watching as they make their ways up and down the glass. I think it’s the unusual angle—we usually don’t see the bellies of our fishes—that grabs the attention. For this entertaining reason, and in some cases for their usefulness in tackling algae issues, I always have a couple of species in my tanks. Over the past few decades, I have kept dozens of suckers from all over the world. This article highlights three of my favourites.
Why suck?
There are plenty of fish with the capability of attaching themselves to objects (or, in case of remora and lampreys, to a living host). If you live in a rapidly flowing environment you have two choices: either swim fast and expend your energy staying where you are (think of trout) or find other way to remain put.
Sucking devices, be they a mouth or modified fins, help many species to hold their positions even in turbulent waters. The keyword is ‘help’. I should add that a mouth or modified fins won’t fully work like the suction cups you use to stick your heater to the glass: they alone can’t hold the fish.
But water flowing over a flattened body with enlarged fins creates a downward pressure that—similarly to formula one cars—keeps a fish firmly fixed. As sucker-mouthed fishes need to swallow their food they can’t maintain a constant vacuum, so without a hydrodynamic shape they would be swept away.
Having closed cups around their mouth could give them other advantages, too. As many of the sucker-type fishes are foragers, meaning that they feed by scraping at aufwuchs, the cup helps them to keep the tiny particles they dislodge in their mouth and not being washed away by the currents.
FAVOURITE 1: The pancake loach
When talking about sucker fishes most people will think of the well-known catfish of the Loricariidae family. These are all South-American species and, apart from
