Follow the schedule with the animals in small separate tubes or dishes.
Many nudibranchs lose all their colour on preservation and you will not be able to separate them easily if you mix them up.
- Narcotise in 1 : 1 mixture of sea-water and 7% Magnesium Chloride solution for 2-8 hours, until animal no longer responds to poking.
- Leave to stand in 10% Formalin or Bouin's Fixative for 24 hours, shaking occasionally. Beware these fixatives are dangerous chemicals and should be used in a fume cupboard or in the open air.
- Wash in tap water for 1 day - shake occasionally.
- Store in 70% Alcohol with label.
- 7% Magnesium Chloride Solution - 70 gm Magnesium Chloride dissolved in 1 Litre of distilled or deionised water. Do not make up in salt water, the osmotic strength must match seawater.
- 10% Formalin - 1 part full strength Formalin (40% Formaldehyde solution) mixed with 9 parts seawater.
- Bouin's Fixative - 375 ml saturated solution of Picric acid, 125 ml Full strength Formalin Solution, 25 ml Acetic Acid (Glacial). The Picric acid solution can be in seawater. Beware - Dry Picric acid is explosive and tiny quantities permanently dye anything they touch yellow.