| POLY BAGS The thickness of a poly bag will have a lot to do with the success of
shipping the critter. Too think and the bag could be punctured by a dorsal or pectoral
spine. Some fish "thrash" around in the bag when they are bagged increasing the
chances of puncture. If the chosen bag is too thick the gas transfer properties of the bag
will be completely loss and when the "balloon" is formed, the creases and folds
of the thickest bags could create some liabilities of the fish.
Remember that the thickness of a bag has little to do
with it's quality. Thickness is thickness and quality is quality. Don't get hung up in the
same errant thought process of some of your shipping partners and start to think that
using a thinker bag will reduce the chance of the bag leaking.
We prefer to use the thinnest bag for the particular application. Our favorite thickness is 1.5 mil. A 1.5 mil
(short for 1/1000th of an inch) bag is thin enough to be easy to knot and folds easily to
form good balloons for shipping various products. The bag is however a little too thin for
some of the largest fish and the spined ones (Corydoras, Angelfish, Madtoms etc.). A good
deal of gas transfer apparently takes place as some species (which are "light"
on their O2 consumption anyway) such as Bettas and Killifish have been known to survive a
week or more in such bags...Bettas and Killifish are tough fish.
The 1.5 mil bags are our number one choice in
thickness.
We also like to use 2 mil bags for some fish in
combination with either a 1.5 bag or a 4 mil bag. The 2 mil is thin enough that a good
balloon can be formed yet thick enough to be able to stand up the spines of young fish. We
frequently found ourselves bagging a fish in a 1.5 unit and using a 2 mil for the second
layer (depending on the species and the size of the fish). We used 2 mil with quarter
sized Angelfish.
The thickest bag we used is a 4 mil bag. Four mil
units offer about the most protection form spines that one can get without using a poly
box rather than a bag. These bags are very thick. If they seem thicker than the drop cloth
one uses to protect the floor while painting there is good reason...they are. These are of
course used with larger fish and fish with spines. All of our Angelfish pairs are shipped
in 4 mil bags. This thickness is typically used by wholesale shippers. It's easy for them
as they don't have to think about the appropriateness of the thickness and
knotting?...most of the wholesalers use a stapling device (called a "clipper")
to seal the bags. The strenuos work of knotting or rubber banding a thick bag is not an
issue when using a clipper. |