Tips for good upkeep of your tank gadgets
By Ron Hill
The tools used every day for fish culture tasks are extremely important to the welfare of the fish and the efficiency of workers. Which tools you choose for your tanks depends on the tank setup and the needs of the fish stock.
For the best biosecurity, each tank should have its own set of mort nets – instead of sharing between tanks. This is likewise true with other tools that are practical to be tank-specific.
Even though tools are tank-specific, it is important that they should still be disinfected regularly. Fish culture tools have a notoriously high upkeep. Many tools used for fish culture, notably mort nets, are custom made or repurposed into improvised tools from common off-the-shelf items. Actions such as mort picking, fish capture and tank cleaning put a lot of wear on tools causing frequent breakage, as do the fish themselves. Broken tools can be very ineffective in getting the job done, but are also hard on the fish. Thus, they should be removed from service and fixed as soon as possible.
Whatever materials you choose for your tool construction, they should be easy to disinfect, such as plastic and aluminum. Fibrous materials, like netter, should be soaked in disinfectant regularly.
Mort nets and capture nets
Mort nets, most of all, frustrate facility technicians; least appealing of all is working on the nets that touch the dead fish. Because of their often-improvised nature, the wear-and-tear of everyday use on mort nets requires their constant upkeep.
Each tank must have its own mort net for the sake of biosecurity, which means there can be a significant number of tools to take care of. Worse than fish getting through the holes are fish getting stuck in the hole and suffering or dying. Time must be spent to repair mort, capture and seine nets. Unfortunately, this job can often be overlooked. Make sure to make the needed repairs sooner before the next use. All too often, staff setup for a fish move or other event only to find out once they have started the task that their dip nets are in disrepair. This then leads to workers scrambling to find “the good net” just so the task at hand can begin. Holes should be repaired immediately, or nets should be taken out of service. Seine nets should be unrolled and inspected for holes before going into use.
Brooms, brushes and fish movers
Brooms and brushes are essential tools to help with daily tasks. Pool brushes and floor brooms are great tools for cleaning the walls, floors and tank screen. A long stiff bristle with a good handle is key to applying enough force to get screens properly cleaned.
Another helpful tool for screen cleaning – and one that can be improvised – is the spray wand. Usually made of PVC, the spray wand is a hose extension with a nozzle that allows a jet of high-pressure water to be sprayed through the screen at close range. This jet of water helps remove fouling under the screen, in the sump and in the piping.
Fish movers are an essential tool for clearing fish away from an area in the tank where you need to see or do something, without touching the fish. By pushing the broom through the water in a stabbing motion and stopping short of the fish, a pulse of water hits the fish spooking them from the target area, without contacting the fish.