Where are the eggs?

[Geoff]

I'll explain in more detail why I've concluded what I wrote above.

I had two pairs of young frogs which, on reaching sexual maturity after approximately a year, produced eggs. For the next 7 years they remained healthy and went into amplexus but there were no more eggs. During those 7 years I kept them in a lavishly planted natural-looking tank which, although pleasing on the eye, did not provide any significant changes in environmental conditions in terms of lighting (10 hours a day - controlled by a time switch) or water temperature, which, like yours, was roughly in the 68°F to 70°F range. Their tank was in a north-facing room and never received any direct sunlight.

Eventually, I decided to move things around and transferred the frogs to another tank, which was sparsely furnished with plastic plants, no substrate or artificial lighting, a few short pieces of upturned plastic guttering to provide shelter, a basic air-powered box filter and a sliding glass lid. This tank was situated in a south-facing room, which received direct sunlight (when it was sunny) for a large part of the day, although the tank itself did not. However, the room had a fluctuating temperature range. In winter, there was no heating on in the daytime when I was at work. In summer it got fairly hot (most homes in the UK don't have AC), which meant that the tank's water temperature gradually fell and rose accordingly from the low 60°sF to the upper 70°sF range.

The result was that the frogs started producing eggs again during the first summer of being in the new tank. They did it again the following spring and, even after the males had passed away, there was at least one female who expelled unfertilised eggs in April of one year. Unfortunately, I didn't keep detailed records.

The experience was unexpected and an unintended consequence of relocating the frogs. The main lesson I learnt from it is that what we may perceive as a "natural" tank can sometimes amount to little more than a pleasing visual effect to satisfy our own aesthetic requirements rather than a true replica the frogs' natural conditions.

[mpmistr]

They live in turbid water so this makes sense actually.