How to successfully feed fish during the holiday season


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Although some pets can come along with us when we go on holiday, or visit the kennels or cattery, an aquarium or pond is not so mobile and so we need to find a good way of looking after our fish while away. A lot can be done prior to you going on holiday, such as changing the water and cleaning the gravel and filter, but there is one activity that must continue, and that is feeding.

By Dave Hulse, Technical Consultant at Tetra.

There are several choices available. Firstly, you could choose to simply not feed your fish while you’re on holiday. This won’t be an issue if you are away for a day or so, but a lengthy absence is likely to cause problems. Some fish are able to deal with periods of fasting (not feeding) such as sedentary carnivorous fish, which can cope with larger intervals between feeding. During this time, scientific research on fasting in fishes shows that stores of energy in muscle protein or fatty tissue will be recruited in the absence of food. In some species this is shown to raise levels of the stress hormone cortisol, which can continue even after the fish have been re-fed, though there is much contradictory evidence across the species tested. One study using the estuarine goby, Gillichthys mirabilis, showed cortisol levels six times higher than usual following 20 days of fasting and it took seven days to get back to controlled levels once the fish were fed again. However, trout, (Onchorynchus mykiss), showed lower cortisol levels in fasted fish.

We cannot say for certain that the absence of feeding your fish for two weeks while you are on holiday is not going to have deleterious effects on their welfare and so it is best practice to ensure you have methods to keep your fish fed while you’re away.

Automatic feeders are another option; set to dispense a precise amount of food at set times during the day. These are used by many fishkeepers as the usual feeding method, so the holiday period just requires enough food to be placed into the feeder to last the duration of the break. Another option is to get a friend or neighbour to feed your fish while you are away – this can be useful as long as they have a bit of training beforehand and you are contactable if there is a problem. The final option is to use a holiday feeding block, which releases small pieces of a low protein food into the water to keep the fish going in your absence, and it is these holiday feeds that I want to focus on here.

The fish feed section of your local aquarium shop will contain ‘holiday feeds’ with options available for shorter and longer periods of time. Traditionally these were white blocks, whereby small morsels of food were embedded in plaster-of-Paris. This would slowly dissolve in the water releasing the food for the fish to eat. We have recently realised that the dissolution of the plaster-of-Paris can raise the general hardness of the tank water to unacceptably high levels. It’s for this reason that Tetra’s Holiday food uses a jelly-like media to carry the small morsels of food, which doesn’t negatively impact on water chemistry. Tetra has also recently introduced a new ‘Menu’ format, which offers protein-rich pellets and tasty krill for a more diverse diet while you’re away.

However, it’s important as fishkeepers that we realise our fish may not associate a large holiday feeding block with food! Fish are inherently cautious of new, strange objects in their habitat, (we call this neophobia, or ‘fear of the new’). This new object could be a predator, it could be a competitor or it could conceal many other dangers. Therefore, popping a holiday block into an aquarium the morning you leave for your fortnight’s break really is not a good idea.

The best thing to do is run some trial sessions with smaller pieces of the holiday block well before the holiday, adding a small amount of the fish’s usual food at the same time. It can take a while to convince the fish that this large strange item is not only unthreatening, but is also food.

Though these holiday blocks are low in protein to minimise pollution in the tank, (Tetra Goldfish Holiday food has a mere 3% protein whereas typical fish feed may contain 30-40% proteins), there will still be a small demand placed on the tank by the addition of this holiday food. If not eaten by the fish, those food morsels will slowly break down, liberating tiny quantities of solid and dissolved wastes and consuming a small amount of dissolved oxygen as this occurs. In a sensibly stocked and properly filtered, mature aquarium this is not an issue. However, holiday foods really should not be used in tanks that are brand new, that are overstocked or unfiltered.

It's also important to follow the guidelines on the packaging to ensure you’re using the right amount and feeding in the right way. Many come in an inner packet to keep the food fresh and this needs removing before using or you may harm your fish – you’d be surprised at how many people miss this when opening the food and end up placing the block in the aquarium still in its film.

When used correctly, holiday foods make a great option for keeping fish fed with a healthy diet. If you’re overly concerned about your fish, there is always the option to set up a camera where you can keep an eye on them from your mobile allowing you to still enjoy a well-earned break!