Lepidocephalichthys thermalis spawning behavior

By Naomi Delventhal

Although loaches are traditionally considered to be among the most difficult to spawn freshwater fishes, an increasing number of spawning reports are being made. Lepidocephalus thermalis is a small spotted loach species that has been kept by aquarists for many years, although to my knowledge no one has until now reported the spawning behavior.

I acquired 5 individuals in the spring of 2000 and placed them in a ten-gallon planted tank along with two Pangio anguillaris (Eel loaches). These were fed on a variety of food items. The water was filtered with peat, although it was still fairly hard and alkaline. As summer arrived the water became very warm, at which point the Lepidocephalus became increasingly active and nervous. To cool the water I removed the aquarium's cover, which caused the evaporation of about a gallon of water a day. Each day I replaced the evaporated water with a gallon of cold water, which dropped the tank's temperature quickly by several degrees. This, I hoped, would simulate the natural rainy season.

One evening in early August I noticed a dramatic increase in activity. Three of the Lepidocephalus were chasing the fourth (which appeared to be a female) throughout the tank. Just after 9:30 pm spawning began. One of the males grasped the female, apparently by the barbels and pectoral fins. The pair curved their body in an embrace and dashed upwards, breaking the water's surface. As they fell, as many as thirty bright green eggs were released, which slowly landed among the plants. They appeared to be only slightly adhesive. This spawning process occurred about forty times with different males, but at last began to subside at about 11:00 pm. I left the eggs with the adults, which did not seem interested in them. Unfortunately no fry appeared.

As time went on, I observed the Lepidocephalus spawning about 5 more times. These spawnings were also stimulated by environmental changes, which were, however, less dramatic than the first time. I attempted to collect the eggs off the plant leaves but they fungused after a couple of days. I suspect the hardness of my tap water had a negative effect on their viability.

I am actually a little surprised that spawnings of this species are not more commonly reported, as mine spawned so willingly. Probably this lack of spawning reports is in part the result of hobbyists overlooking this very interesting species in favor of more colorful ones. I also think that Lepidocephalus probably spawn fairly frequently in aquaria, only they do so during a time when the aquarist is not around to observe them.

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