We answer some of the most Frequently Asked Questions regarding Tropical, Marine, Coldwater. If you have anymore questions please contact us. & Ponds.


Q. Why does my pond turn green?
A. Simple… The answer is sunlight. To help prevent it the best remedy is an ultraviolet steriliser, which is a permanent solution, as long as you replace the ultra violet light every 6 months. Water chemicals can also be effective. (Please ask staff for their recommendations).

Q. I have heard that salt is good to put in your pond but how much do I add?
A. We recommend 1/4oz per gallon, this will help keep your fishes’ immune system high to prevent diseases.

Q. How will I know if my fish are unhappy?
A. Most fish will separate themselves away from the shoal when something is starting to go wrong or if the fish is distressed.

Q. Can I put any treatments into my pond?
A. No, please be advised by our trained staff. Some fish can not tolerate certain treatments. Remember the staff can only help if they know all the information.

Q. Can I put Koi & Goldfish together?
A. Yes you can mix Koi and Goldfish in the same pond but be aware that Koi create more waste and require a larger pond and filtration system than goldfish.

Q. Which filter is best for my pond?
A. Please ask one of our trained members of staff and they will advise you which filter system in best suited for your pond.



Q. Can I put a Coldwater fish straight into a bowl with tap water?
A. No, the water has to be matured and treated for chlorine and chemicals before a fish is introduced into an aquarium.

Q. Why does my goldfish lie upside down?
A. It sounds like a strange question but one of the most asked questions at Hollybush. This is a symptom called ‘Swim Bladder’. To rectify this problem feed live food and add tonic salt, (Please ask our staff for dosage instructions).

Q. Should I put a filter in my tank as it’s just for goldfish?
A. Every aquarium should have a filter even if it is for goldfish. Remember coldwater fish are larger than tropical fish, so obviously they eat more and in turn create more waste. Without a filter the water would become cloudy and polluted.

Q. Can I put goldfish and fancy coldwater fish together?
A. Not really, goldfish are quicker and more domineering than ‘fancy’ goldfish.

Q. Are there any ‘cleaner’ fish for my coldwater tank?
A. Yes not as many as for tropical tanks but fish such as hill stream loach help keep a coldwater aquarium clean.



Q. What is the best temperature I should set my heater at?
A. Most of our tropical tanks are set at 770F. Some fish prefer higher temperatures than other and our staff will always advise you when purchasing such fish.

Q. Should I leave the light on all the time?
A. No definitely not, the light is purely for the growth of plants and for your visual enjoyment.We would recommend between 6-8 hours a day.

Q. Should I leave my filtration on all the time?
A. Yes this is a very important part of your aquarium and should be left on 24 hours a day. As soon as your filter is turned off all the good healthy bacteria inside it starts to die and this can affect your water quality.

Q. How much water do I change and how often?
A. We would recommend a 20% water change every 2-3 weeks regardless of whether water quality is good. (Don’t forget to test your water before you do a water change).

Q. How often should I realistically test my aquarium water?
A. Ideally once your tank is established you should test the water once a week and before you purchase any new fish.

Q. How do I rectify a water quality problem?
A. There can be many reasons for a problem, don’t be afraid to ask for advice as we can help you. We have many years experience between us!

Q. When can I introduce my first fish to the aquarium?
A. Probably the most asked question, ideally we would recommend between 2-4 weeks, obviously if your water quality is good. Always get your water tested before purchasing any fish.

Q. How do I know what fish to put together?
A. We can help you choose what fish are best kept together as all of our staff are trained. Our tropical fish room also has labels about each of the fish with a short description of their temperament. We also use a traffic light system showing you how aggressive or how difficult a fish can be to keep. But remember no two fish are the same in temperament.

Q. I have seen some pretty colourful fish called Cichlids, can I introduce these into my community tank?
A. These fish may be small and colourful at the moment but they will soon grow into large aggressive fish. They also require a higher PH than community fish, so are best kept in a species only aquarium. Please ask a member of staff if you are interested in Cichlids.



Q. Is it harder to keep marine fish compared to tropical fish?
A. Not really although you do need more patience and you must realise that you won’t be able to keep as many fish. Testing and looking after your water quality should be no different between tropical and marine aquariums.

Q. Can I keep corals with fish?
A. Yes you can, but this does make a difference to what fish you can keep. A lot of treatments can not be used with corals or invertebrates, although there are alternatives. All our marine labels in store will tell you if a fish is reef compatible or not, or you can ask one of our staff who will be happy to help.

Q. I have heard that lighting it very important for marines, is this true?
A. For a coral tank yes it is, as these need high intensity lights. We supply a large variety of lighting systems so please ask. However for a fish only system, the lighting isn’t as important.

Q. Is it essential to have a protein skimmer?
A. Not essential, but they are very beneficial at removing organic waste before it can break down and release nitrogen compounds. We recommend that tanks over 50L should be fitted with a protein skimmer.

Q. Is a pool UV sterilizer the same as a marine one?
A. No, they are built slightly differently and a marine UV is built to kill parasite/bacterial spores as well as algae spores.

Q. Is living rock essential to have?
A. No, living rock is as it suggests, living. You can get good living rock and bad. Good rock mainly because it can help with the filtration and provide beneficial bacteria, but on the other hand you don’t really know what is hiding in the rock. The other reason is that some living rock is taken straight from the ocean which in turn damages reefs. This is the reason that our live rock is from a sustainable source.

Q. The fish are expensive, should I quarantine my new purchase?
A. The answer to this is always yes if possible. All of our fish are quarantined before being sold but we recommend that all fish are quarantined before being added to your main display tank.

Q. Can I over filter a marine tank?
A. Simple answer is no. The more filtration the better which is the same for every tank or pond. But be aware that too many diffused bubbles in the tank can permeate the fishes skin. A simple way to solve this is to make sure that all powerheads and outlets are below the water level.