The results of my experiment are in: kuhli loaches prefer rocky gravel.
This was statistically significant. Rocky gravel was the most popular choice, followed by small gravel, with sand being used the least. Rocky was chosen almost twice as often as the other two substrates combined. Tank was set up with those three choices of substrates. They had a PVC pipe in all three choices, and one plastic plant, and were fed equally over all three substrates. This went against my hypothesis that they would prefer sand, and rocky would be the least liked.
Possible explanations: There weren't many hiding spots, so we think they liked the rocky gravel because they could hide better and could burrow under it. During the last few days of the experiment, two took to hiding under the pipe in the rocky gravel. None ever burrowed in the sand (although we did see them sifting through the sand occasionally. Next year, I plan to test this hypothesis again, using a well planted tank so everywhere is shady and they might not need to hide among the gravel.
This is good, because I have large to medium gravel in my tanks. Just thought you might like to know.
This was statistically significant. Rocky gravel was the most popular choice, followed by small gravel, with sand being used the least. Rocky was chosen almost twice as often as the other two substrates combined. Tank was set up with those three choices of substrates. They had a PVC pipe in all three choices, and one plastic plant, and were fed equally over all three substrates. This went against my hypothesis that they would prefer sand, and rocky would be the least liked.
Possible explanations: There weren't many hiding spots, so we think they liked the rocky gravel because they could hide better and could burrow under it. During the last few days of the experiment, two took to hiding under the pipe in the rocky gravel. None ever burrowed in the sand (although we did see them sifting through the sand occasionally. Next year, I plan to test this hypothesis again, using a well planted tank so everywhere is shady and they might not need to hide among the gravel.
This is good, because I have large to medium gravel in my tanks. Just thought you might like to know.