Maidenhead Aquatics Topical Tips - April 2010

The frogs have been spawning, the marsh marigold is flowering like there’s no tomorrow and I’ve had my first sunburn of the season – spring is most definitely here!

Outdoors

All this sun brings higher temperatures and the opportunity to add new fish to your pond. Bear in mind those cold nights mean that deep areas of slow moving or unfiltered ponds can be slow to warm up and newly added fishes can get quite a shock as they dive into the depths if not properly introduced. Typically, fish are floated on the surface of the pond in their plastic bag to ‘equalise the temperature’ prior to being released. As the difference in temperature between the surface and the bottom of the pond can be significant, new fishes will undergo a rapid change in temperature immediately on introduction to their new environment anyway as they seek the protection of deep water. To give your pets the best possible start in their new home, open their transport bag and place them in a clean bucket before gradually adding pond water in small quantities. This gives them the opportunity to adjust to changes in pH, hardness and all other water parameters slowly. Once the bucket is full (after around 30 minutes or so) lower it into the pond and allow the fish to swim out at their own pace. As an easier alternative you can use their plastic bag in a similar way but whichever method you choose, make sure the fishes get a taste of what’s to come. Remember also that active species such as Golden Orfe will readily jump out of an open-topped container.

With so many pond fish to choose from, it can be tricky to know what’s best for your situation. Let’s have a look at some of your options:

Goldfish – Traditionally the pond fish, the good old-fashioned goldfish is hardy, popular and easy to breed. There’s no difference whatsoever between indoor and outdoor goldfish and as long as they are long and streamlined with a single tail, fish from bowls (dirty word that) and aquaria can be added to an outdoor pond where they will thrive and generally enjoy a much longer life. Fancy varieties with exaggerated body shapes such as fantails, moors and ryukins are a poor choice for garden pond life and do better in a large aquarium away from predators and competition. Long-finned goldfish are known as ‘comets’ and are nearly as hardy as their short-finned relatives. All of the goldfish varieties are friendly fish that will readily mix and happily cross, often producing some interesting looking offspring! Occasionally, some breeders will cross fancy goldfish with pond varieties to improve colour and for this reason we’re very careful to source our stock from cold parts of the world were fishes are bred to withstand the rigours of the British winter. All of the goldfish varieties can grow to around a foot (30 cm) in length.
Shubunkin – The name that lots of people struggle with, ‘shoe-bun-kins’ or ‘shubs’ for short, are a colour form of goldfish and will happily swim and interbreed with them.
Sarasa Comet – With stunning red and white colouration, sarasas are a good alternative to koi in smaller ponds and are just glamorous goldfish with all the same requirements.

Canary or Lemon Goldfish – Despite the name this recently developed goldfish variety neither sings, nor tastes any different to normal goldfish but is a lovely yellow shade that looks great when mixed with sarasa comets.

Koi – Although not seen as the status symbols of twenty years ago, koi carp are still great aquatic pets if kept properly and are firmly in the ‘Labrador with fins’ category of aquatic pet. Properly in this case means a large volume of filtered water and a stocking level of around 500 gallons/2,000 litres of water per fish. Being carp, they love to forage through the mud and will stir up any sediment and completely trash any pond plants they encounter. Like any big fish, koi will be a problem if purchased for a small pool with plans of increasing the size as they grow, as in small ponds they are often stunted and misshapen unlike the sleek, beautiful fishes that they can become.

Ghost Koi – Are the result of crossing a single-coloured koi with a wild-type carp and are normally hardier than their posh parent. The ghost part of the name comes from the fact that in a pond the more brightly coloured head and back are the only visible part of these friendly fish. ‘Ghosties’ have all the personality and destructive abilities of koi but are more forgiving of water quality lapses or overcrowding. Despite their durable nature, they are best given the same conditions and allowed to thrive. Like koi, they can quickly grow to over 2 feet/60 cm in length and many fishes are considerably larger.

Golden Orfe – Are really under-rated pond fish but do have a couple of quirks that need to be mentioned. As they are originally a colour form of the European Ide, they are a river fish and demand high oxygen levels. This means that they will suffer in small pools with little water movement and ideally should be kept in situations where large filters or waterfalls mean that they can enjoy swimming in a current. This same high-energy swimming often leads to them jumping out of smaller ponds. One massive advantage they have over carp is the fact that they don’t eat plants, making them a far better choice for large, planted pools. Orfe are hardy fish and you don’t often see a sick one – a good job as they’re sensitive to many of the chemicals found in some pond treatments and new tap water. Always check the labels before using any disease treatments and make sure that you use a good dechlorinator when adding tap water to your pond. Orfe are fast growers and can reach 18”/45 cm within a few summers.

 

Golden Rudd – Are the fish that most people really should keep instead of goldfish. An ornamental form of a native species, they are hardy and prolific to the extent that an established population in a planted pond can provide hours of delight for water gardeners, kingfishers and herons. If you’re looking for a native fish for a large wildlife pond, these are the one to go for and despite their larger size of around 12”/30 cm; are far less destructive to other pond creatures than fishes such as sticklebacks.

Green Tench – Are a fish that really lean on a reputation gained in the early days of water gardening. A dedicated bottom-dweller, this native fish was sold as a combination of pond vacuum and ‘doctor fish’ in the belief that it’s body mucous was helpful in healing wounds of other fish. Nowadays you are more likely to see the golden ornamental form – not least because the olive-green colour of wild-type fish makes them very difficult to spot, even in clear water. Tench will surface from the depths to feed together with other pond fish and add a bit of mystery to the garden pond. Easily sexed by comparing the large, spoon-shaped pelvic fins of males with the smaller counterparts of females, these are great addition to the fish community and the smaller gold form seldom reaches the 24”/60 cm that wild green females can attain.

Sterlet and Sturgeon – Are primitive ‘sharky-looking’ fishes that have little in common with the other carp family species that make up the overwhelming majority of pond fish. These are fishes that tend to pace the pond perimeter and lack the swimming skills needed to avoid thick growths of blanketweed or pond plants, often become fatally entangled. They also love the cold and thrive best in big, deep ponds with good filtration and water movement where they can be fed year-round. Like orfe, certain chemicals can be problematic for these fish and the same precautions apply. Related to some of the biggest freshwater fishes in the world, sterlets are the baby of the bunch and reach around 36”/90 cm with sturgeon capable of doubling this size.

Whether your fish are new additions or well-established residents, it is very important to feed a good diet at this time of year to get them into peak condition for the warmer months and the coming spawning season. As long as you don’t show them the label, goldfish types will thrive on diets made for koi and will often show brighter colours and better growth as a consequence. General pond fish foods tend to be lower in expensive ingredients such as proteins and colour-enhancers but are a great way of training your fishes to view your arrival as a good thing and come and beg for food. In many well-established ponds with a low fish population, feeding is a supplemental treat that can be used to enjoy some contact from otherwise timid creatures and if you offer an amount little and often they will soon learn to emerge from the depths to feed. As is the case with aquaria, heavy feeding can lead to water quality problems and excessive algae growth.

Many people would have seen their resident frogs arrive en masse last month to spawn and now the garden pond is home to many amphibians that can be harder to spot at other times of the year. Toads normally start spawning later than frogs and their long ropes of spawn are often wound around plants in the deeper areas of the pond that they tend to prefer. As their eggs and tadpoles possess the same distasteful chemicals that the adults use for protection, toad tadpoles are more likely to shoal in open water than frog tadpoles and can often be seen in ponds where fish would have eaten their more palatable relatives. As they grow they also remain black, unlike the speckled colouration found in older frog tadpoles. As adults, their copper-coloured eyes and rough skin make them easy to tell apart. It often seems that there are too many tadpoles for your pond to support but one of the main predators of them are the newts which by now will be well into their longer spawning season. Male newts have a flamboyant breeding dress to impress the females with and unlike frogs and toads the females will lay their eggs individually in submerged plants and algae, rather than putting them all in one basket.

These Javan toads demonstrate the typically warty skin found in many toads worldwide

Indoors

As I mentioned above, the rising temperatures mean that if you have a pond hardy goldfish living in a bowl or aquarium indoors, now is a good time to think about giving it a dream retirement to a pond environment. A commonly held misconception is that goldfish are easier to keep than tropical or marine fishes and it has to be said that it’s simply not true. A much better option for small aquaria is the amazing white cloud mountain minnow (Tanichthys albonubes) – an adaptable and hardy little fish that thrives in an unheated, filtered aquarium. These little fishes are now bred in a number of forms including a golden yellow and a long-finned morph.

In the same way that outside toilets used to be the norm, unfiltered containers for keeping fish should also be a dim and distant memory. Just because it can be done doesn’t make it right. Sermon over, there is one species of fish that can be kept in a well-managed small tank at room temperature. Closely related to the Siamese fighting fish or Betta, the Paradise fish (Macropodus opercularis) is an air-breathing inhabitant of swamps and paddy fields of South East Asia and happily tolerates a very wide range of temperatures. These fishes can be scrappy with each other and males can be violently antagonistic if crowded. For best results keep a male with two or more females in a well-planted set up, or a single male in smaller tanks. Having been kept in European aquaria for the best part of 200 years, this fish now exists in a few colour forms – albino, blue and red. All of them are great fish to keep but too aggressive for the average community tank.

It’s not just our weather that’s improving, as tropical countries come out of the wet season life gets easier for our coral farmers in Indonesia and water clarity improves. This makes selecting the best corals easier and sunnier conditions promote growth and colour intensity. In addition to these cultivated corals, a number of our stores are now selling ‘frags’ produced in store – look out for these at your local marine specialist branch.

Because we all love a happy ending, it seems fitting to comment that after the fire that ravaged the Farnham store I’ve been observing some of the livestock that we worked into the night to evacuate from the soot-covered systems. It’s no easy task moving 15,000 fishes and invertebrates but they’ve settled nicely into nearby stores. I was particularly gladdened to see one of my favourites – a Comb or Elegance coral (Catalaphyllia) that I featured back in January. This defiant animal puts the ‘hard’ back into ‘hard coral’ and was sat in the Guildford store ready for the next adventure!