Food Lab

Purpose:
Weakly electric fish are known to use electroreception as a means of locating food. In the food lab you will observe how the EOD alters when the fish is exposed to food.
Materials:
Pantyhose: unlaundered with a fairly loose weave
One clear plastic tube: approximately 16.5 cm long and 3.0 cm in diameter

Petri dish
1/4 cube of frozen blood worms

Large pair of tweezers
Waterproof tape

Live weakly electric fish
Oscilliscope

preamplifier
Electrode

Amplifier
55 gallon tank

Procedure:

- Take plastic tube and make a 1 cm in diameter hole in the top.
- Tape the top of the petri dish to one end of the tube. Make sure that it is fully closed. If you do not have a petri dish, you can use any other clear object which can be used in the same way or use pantyhose.
- Capture the fish inside tube. Try to do this as gently as possible so as not to stress the fish. Seal off the open end with pantyhose and rubber band.
- Let the fish adjust for at least twenty minutes. This raises the accuracy of the data by allowing the fish to become acclimated to the altered conditions.
- Place tube at the bottom of the tank with the petri dish end against a wall and place the electrode at the opposite end. If possible, try to arrange the fish so that the tail is on the side of the pantyhose so that the signal will be stronger. (This is optimal but not necessary.)
- After the required twenty minutes of acclimation time, observe the fish and its EOD for five minutes, record amplitude, behavior, and frequency every 15 sec using the observation sheets.
- As gently as possible, pry open the end of the tube with the glass petri dish and insert a 1/4 of a cube of frozen of blood worms (should be completely thawed).
- Immediately begin recording. Record amplitude, behavior, and frequency every 15 sec for 10 min.
- Make any other measurements you feel necessary.
- Release fish.