Endeavour's astronauts today tested a system to deliver intravenous fluids in weightlessness, a step toward meeting the possible medical needs of astronauts who stay in space long-term.

"We're very happy with the results we got," said NASA scientist Charles Lloyd, who is overseeing the experiment from Earth.When patients on Earth need intravenous fluids, a bag is hung above them and gravity propels the liquid through a tube into the body. That would not work in space, where there is no gravity.

The system designed for NASA's proposed space station Freedom uses a pump to administer liquids. The system also sterilizes shuttle water and mixes solutions from concentrates, reducing the need to transport ready-to-use medical fluids to space.

Astronauts Jan Davis and Mae Jemison tested the pump today by moving sugar and salt solutions from one bag to another through an IV tube. Jemison, a doctor, also gave an IV to a mannequin arm with simulated veins.

The system was tested on a previous shuttle flight, but computer problems interfered with the collection of data, Lloyd said.

Endeavour's eight-day Spacelab flight is due to end with a Sunday.

On Thursday, the seven-member crew got some bad news and good news regarding their orbiting menagerie: two carp, 180 Oriental hornets, 7,600 flies, four adult frogs, as many as 440 space-bred tadpoles and 30 fertilized chicken eggs.

Fungus was spreading on one of the carp, said Mark Lee, the astronaut in charge of the shuttle laboratory. The fish was lethargic and barely responding to light.

The listless fish for days has been tangled in a cable that connects to electrodes on its brain. Japanese researchers are monitoring the electrical activity of the brains of the fish, using light as a stimulus.