#hillstream

And this really got me thinking about how much the hobby oversimplifies habitat conditions that fishes interact with in extremely complex ways.

Look at hillstream tanks. Fast water fish species use areas of drastically different flow rates throughout the day to exhibit different essential behaviors. Flow rate is exceptionally important to them in habitat choice. In the wild, they can move between these areas as they please and completely avoid areas of a stream that can't meet their needs.

But in the hobby, we simplify this to just mean that the fish like fast water. All hillstream tanks are essentially the same - we might consider turnover rates a bit, but there's no empirical basis to the flow rate we provide. Its not like most people are researching the flow rates of the streams their fishes come from at all, never mind how the flow rate varies in different microhabitats and how their species moves between those microhabitats. We pump in super fast water and don’t consider what the flow rate actually comes out to be, what flow rate our fishes would have available to them in the wild, or if they use more habitats than just the high flow we add at the surface and the areas of reprieve we provide at the bottom via our hardscape/decor.

(Though this of course only works for habitats where that information is available - for my Tachysurus trilineatus, for example, I know there is little information beyond a morphological description available about them.)

And this applies to other habitats too, especially other extremophiles. I know I've harped a ton on blackwater tanks in the past - how the hobby acts like all blackwater habitats are identical to the Amazon River, when in reality they are incredibly diverse. Some have plants, flow rates vary, leaf litter varies. There is more to consider, but we don't.

This makes me really want to rethink every tank I keep. For another example, I know Pseudomystus siamensis occurs in major river basins, but a fish at that size is probably found in the shallower, more vegetated areas of the rivers themselves or in the lower order streams that feed into it. Am I providing the right habitat? Does my tank provide enough of a variable space to meet all of my fish’s needs? I'm not sure.

In the species I keep, of course, there's not much information out there. That's true of Southeast Asian fishes in general, and why I decided to study them as a profession. There's so much to learn.

Major update to my 20L lower Himalayan hillstream tank! After months of aging and plant growth I've begun stocking it with scaled beauties!!

Hillstream loaches cleaning leaves