Temperature

[mike_the_zealot]

I thought I saw a comment about lower temperatures when keeping plecos. I usually set all my tanks to 78-80°F. What temp should I keep my pleco tank at? I have an L128, and hopefully an L018 by the end of today ;)

I've partially subscribed to the idea throughout my fishkeeping that higher temps tend to promote faster growth, am I a moron?

[Silurus]

Not all plecos live comfortably at the same temperature. This depends primarily on their habitat (e.g. hillstreams tend to be cooler). Your L128 will not do well at 78-80 degrees (though the L018 probably would). Check the Cat-eLog for optimal temperatures for your plecos.

[Shane]

Just to expand on what HH said... Loricariids are found in just about every ecological niche in South America. This includes every type of water chemistry and temperature range that exists on the continent. The only exception seems to be (and I would not be surprised if it was disproven) very, very high mountain streams. These areas have been colonized by astroblebids and trichomycterids.
Many hobbyists tend to have the idea that "plecos" all have similar requirements when nothing could be further from the truth.
Contrary to what many people think, even the tropics have seasons that affect water temperatures. In the rainy season, for example, the water becomes cooler not because the rivers are farther from the sun (as would happen closer to the poles) but because cloud cover blocks the sun's direct rays, increased run off enters the lowlands from mountain streams, and the rain agitates and cools the water itself.
Still another factor is that ninety plus percent of collecting trips take place at the end of the dry season because it is easier to collect fishes. The problem is that this is when the water is at its hottest. When hobbyists (and scientists) record water values, they are probably the worst water values the fishes can tolerate. This gives a false impression to the hobbyist that tries to use these water values as a guide.
I have collected Rineloricia in the dry season in stagnated river sections where the dissolved oxygen was very low and the temperature very high (maybe as much as 92F). I have collected the same sp. in the wet season in fairly fast flowing creeks with temps in the low 70s.
In an ideal world, we could replicate this in the aquarium. However, usually only serious hobbyists trying to bred fishes mess with water temperatures.
As a (very) general rule of thumb, 76-78 would be a happy medium for most fishes and hence most loricariids. Hillstream loricariids, like Chaetostoma, are much happier in the low 70s. You can certainly raise the temp to the low 80s for a few weeks if you are trying to spawn something, but the temp should eventually be lowered to something more tolerable.
One final factor is depth. Large fishes stay deep and small fish take advantage of the shallows. Small loricariids like Hypoptopoma and Otocinclus will tolerate higher temps longer than larger loricariids such as L 128. Even in the tropics, deeper water can be much cooler. While swimming in the dead center of the Amazon between Colombia and Peru, I held my breath and swam down as far as a I could. I was shocked when the water (about ten feet down) became COLD! It must have been in the low 70s and this is where many larger Amazonian catfishes thrive.
-Shane

[mike_the_zealot]

Nice! Thanks guys =)

I had a much larger message which included words of praise for your impressive knowledge and willingness to share, but I sounded like a little girly man who watches too many soap operas.

I think I'll set the temp at 77°F, which seems at the top of the L128's range, and the bottom of the L018's, according to the Cat-eLog.