Abstract: The invention relates to a plant holder with several essentially identically shaped elements (2), which are arranged in a vertical position when in use, and at least one supporting ring (3), which is arranged in a horizontal position when in use, which includes easily removable retention devices for retaining several vertical elements (2) along the perimeter of the supporting ring (3) and at heights corresponding to the vertical elements. The vertical elements (2) may exhibit an essentially rectangular profile. Recesses (10) for acceptance of the vertical elements can be arranged along the supporting ring, of which there is at least one, while protrusions (12) can be arranged along the lateral surfaces of the vertical elements which, when assembled, snap into corresponding grooves (11) in the recesses in the supporting ring (3).

Abstract: An effective track system for guiding a rolling hamster ball includes straight and curved track sections, placed end to end. Each track section has a base and paired support rails protruding upwardly from the base for supporting and guiding the pet exercising ball along the track.

Abstract: A breeding apparatus comprising a breeding water tank, an ozonizing device, an activated carbon device and a breeding water circulating device wherein breeding water of sea water or a mixture of sea water and plain water is circulated in series in these devices, and the ozonizing device is located at the upstream side of the activated carbon device with respect to the flow of the breeding water.