Tag Archives: nutrition

Something Fishy! (1)


After doing my dissertation on goldfish nutrition, bringing the fish back home with me, and them surviving the long journey from university, I am quite impressed at how well my goldfish are still doing after 2 years! I also maintain my dad’s tropical fish tank with somewhat smaller and different species to my Comet goldfish (pictured below). This tank has been going since I was a kid, just replacing stock as required.

One of my Comet Goldfish

There are some key factors in well maintaining a fish tank, which I have decided to cover in 2 parts so that I avoid writing an essay! So here it goes…

Feeding

Food varies with species. There a many forms on the market. Flakes are the most common/ popular, as are pellets. Live and frozen food are also popular choices for meals and/or treats – again, this depends on the fish species and dietary requirements.

Flakes and Pellets

The brighter coloured the flakes are, the worse they are for the fish as they are filled with additives and colourings! Pellets are harder to tell by colour, however, the best kind you can get is from a reputable brand, not a supermarket’s own brand (this goes for flakes too).

Pellets Flakes
Pellets                                        Flakes

Ensure that you feed the correct flakes for your tank species – fish from different climates, habitats and water-types have different dietary requirements – according to what they would eat in the wild. Tropical flakes for tropical species, cold-water flakes for cold-water species, and marine flakes for marine species. Pellet-wise they can be more species specific than just water-type, for example; Catfish pellets specifically designed for catfish, sinking pellets for general bottom feeder species, and another example being cichlid pellets designed specifically for the diet of cichlid’s.

Live

Mealworms: live mealworms need their heads crushing to prevent them eating their way out of the fish’s stomach). These may also need cutting up if they are too large for your fish – do not feed anything too big for your fish to swallow, as fish can choke too! It’s difficult to do the Heimlich-manoeuvre on your fish!

Brine Shrimp: these can be purchased in many aquariums and pet stores in a bag of water. They will live approximately 5-7 days (slightly longer if they are refrigerated), but ought to be fed to your fish A.S.A.P to prevent them from dying before your fish get their dinner! Do not feed dead brine shrimp to your fish as it could cause stomach upset.
*Interesting fact – this is what your first “pet” was if your first “pet” were Sea Monkey’s!*

Blood Worm: these can also be purchased in aquariums and pet stores, and come in a bag of water. Again they live approximately 1 weeks, a day or 2 longer if they are refrigerated.  However, with blood worm you may wish to drain the water out as it can turn your tank water red! This can be done by pouring most of the water out; carefully keeping the blood worm in a small amount of water at the bottom, and then pouring that into you tank.

 Frozen Food

Beef heart, blood worm, and brine shrimp are the most common forms of frozen food sold. These can all be defrosted for feeding to your pet fish, for marine or tropical tanks. Cold-water tanks can have the frozen blocks defrosted, or dropped straight into the tank – as it shouldn’t affect the water temperature too much, and is a great and tasty way for your cold-water fish to cool down on a particularly warm day.

These types of food can be the main diet, in the place of pellets or flakes. They can be fed as a treat or supplement weekly or every-so-often, again to replace a flake/ pellet meal or as half-half with flakes/ pellets.

If you have larger carnivorous species of fish (such as an Oscar Fish) frozen mice are often fed, defrosted, via long forceps to avoid bitten fingers! Depending on the quantity and size of the fish, determines the quantity and size of the frozen mice fed.

Other Treats

Depending on if your fish is a cold water, tropical or marine fish; and whether they are herbivores, carnivores or omnivores, will depend on what it needs feeding.

Vegetables (not for carnivorous species!):

  • Zucchini (sliced to appropriate size)
  • Lettuce and Swiss chard (shredded to appropriate size)
  • Cucumber (sliced to appropriate size)
  • Peas (boiled or fresh, or frozen for Cold-Water)
  • Broccoli (boiled or fresh, chopped to appropriate size)
  • Split green beans(boiled and cooled)

Fish treats can be purchased that stick to the side of the tank, and can be nibbled at throughout the day.  These need to be suitable for your tank – tropical, cold-water or marine – just like flakes need to be specific to your tank type. These can be a good way of health checking your fish as the treats can be stuck to the front of the tank, and you can see a lot more of your fish when they come up for a nibble!

When checking your fish out for signs of ill-health, bear in mind some common fish diseases to look out for…

Common Fish Diseases and Treatments

White Spot > Characteristic white spots covering body; white spot treatment

Ich > Small white or grey spots on body; ich treatment

Rot – Fin, Mouth, Tail, Gill > Fungus rotting various parts of the body – fluffy grey or white patches; fungal treatment

Parasites – Gill fluke, Nematoda, Anchor worm, Internal Parasites > There are, as with most species, too many to name individually – both internal and external parasites; various parasitic treatments

Velvet > White/ yellow ‘peppered’ spots all over body; ich treatment

Dropsy > Bloated, protruding scales; anti-bacterial treatment

Head and Lateral Line Disease (a.k.a Hole-in-the-head) > visible holes in the head and along lateral line – at first pin prick size, and then get larger. Swollen lateral line; various “Hole-in-Head” treatments

Tuberculosis (Fish TB) > hollow belly, weight loss, possibly sores;  no known cure – very contagious to other fish, zoonotic (can be transferred to humans) if a human puts bare, wounded/ broken skin into infected tank

Oxygen Deficiency > Water problem – more oxygen needed in water. Gasping for air at the top of tank can be seen, water tests can be done; possible solutions – 50% water change, add aeration, add real plants (naturally put O2 into tank), put filter closer to the water surface to keep the water flowing/moving (adds O2) – see image below.

Filter keeping water flow, adding oxygen
Filter keeping water flow, adding oxygen

The majority of these treatments can be purchased in a pet shop, if not the treatments can be found online.