In 1995, an interesting study was done using ACFs being reared in laboratory conditions. I have included the abstract below if you are interested in reading it:

Lab Anim. 1995 Apr;29(2):152-62.
Growth of Xenopus laevis under different laboratory rearing conditions.
Hilken G, Dimigen J, Iglauer F.

Laboratory Animal Facilities, University Hospital Eppendorf, Hamburg, Germany.
Abstract
Since the European frogs (Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin.

Considering the feeding of Xenopus, the biologists concluded that the frogs should be given a variety of foods, such as, earthworms, slices of raw liver and heart, and dry pelleted food. Live tubifex and blackworms seemed to be the best food for growth and conditioning. They are expensive, however. Out of the four feeding groups, only 2 experienced death - the bovine heart group (3 deaths) and the pelleted food group (1 death). The bovine heart group experienced the poorest growth rate. The death in the pelleted food group was because one frog was not introduced to this type of food in the past. It should be noted that "wild caught" frogs may not adjust well to pelleted foods.

The four feeding groups studied were:
  1. Xenopus pellets
  2. bovine heart
  3. mixed foods
  4. tubifex