How can I soften dry food and remove the air it contains?
Practical advice: How to make dry food sink down easily
Fish of the middle and deeper water layers often do not like to eat from the water surface – they instinctively “know” there is danger by hungry birds. However, freeze dried foods in particular float at the surface for a long time without sinking down.
It is quite easy to overcome this!
Method 1: Soaking
Just fill a small plastic can (e.g. the protecting container of a 35 mm film; for larger food portions an unused plastic coffee cup or the like) with aquarium water by a third, add the according food portion with a plastic teaspoon and slightly mash it. The food quickly takes up water by doing so and sinks down better. A beneficial side effect, especially with rather hard granulates, is that the food becomes softer and the fish like it even better. Finally, using a spoon makes food portioning much easier, and you need not touch it with your fingers anymore!
This method leads to freeze dried food causing true feeding frenzy in the aquarium, even with fish that otherwise hesitate to take it.
Evacuating the air from food using a syringe
If you wish to feed the food almost entirely free from air, and without mashing it, it is recommended to evacuate the air with a syringe (without a needle!). Syringes with 50 ml volume are well suited to do so.
This is how to proceed:
1. The food is filled into the syringe after the plunger has been taken out.
2. Now pour water into the syringe, filling it by approx. a third. Due to the encapsulated air, the food floats at the surface.
3. Now carefully put the plunger back in – only far enough to give it firm hold in the syringe!
4. The syringe is now held with the nozzle directed upwards, the air is pushed out of it.
5. Now seal the nozzle with your finger and pull out the plunger. The air escapes from the food due to the vacuum.
Repeat steps 4 - 5 as required.
6. The food sinks to the bottom after the air has been evacuated and is fed to the fish right away.
Dr. Bodo Schnell