by Derek Lambert
Humble Guppy?! Groovy Guppy more like. Guppies have been, and still are, the most popular aquarium fish of all time. Why? Because they are beautiful, hardy, well behaved, and have interesting sex lives!
Ditch the myths
First of all we have to ditch some myths about this lovely fish (all livebearers seem to be surrounded by them) if you are going to make the most of them. Number one myth is that they need salt in their water. A quick look at the Guppies original distribution shows it comes from mostly freshwater habitats that are predominently soft and acidic in nature. Look a little further and you will find brackish, hard, alkaline water habitats as well. In fact Guppies can happily adapt to virtually any normal water conditions and have done so all over the world.
Ideal water conditions
PH 7, 10 dGH, temperature 75 F (23.9 C)
Next up we have the vegetarian myth. Yes, Guppies will eat vegetable matter, but they are “pigs on fins” and will eat anything else as well. Looking at the distribution of Guppies throughout the world today and overlay a map of the old British Empire and you will see a close resemblence. The reason for this is that the Guppy was posted all over the Empire to help combat malaria by eating mosquito larvae. Would a vegetarian be used for that purpose? Obviously not.
So its captive diet should contain the variety of things Guppies eat in the wild and that includes vegetable matter but also meaty foods like small insects which fall on the waters surface. Apart from variety in a guppies diet, the most important factor to remember when feeding this fish is its internal structure. Guppies have no pouch-like stomach, so food passes along its very long gut in little clumps. These are eaten in the same way, so if a lot of food is offered all at once, the guppies can only swallow a few bites at a time. A couple of minutes later they will be ready to grab some more but by this time most of the food will have been eaten by the other fish or have lost much of its nutritional value. So feed a little several times a day and despite being given the same amount of food as before your guppies will grow bigger.
A gem really worth keeping
For the average community aquarium you really can’t do any better than including a few guppies. They bring life and colour to the tank in a way almost no other fish can. So hats off to the glamorous, gorgeous, groovy guppy - be it ever so humble.
Well we are back to sex, and lets face it male guppies think about this more than they do about food. You will often find articles or books that say if you remove all the male guppies from an aquarium, one of the ‘females’ will turn into a male. Absolute rubbish! These fish are just late sexing out males or old females which develop male characteristics. The late sexing out males seem to wait until the dominant male in an aquarium has died or been removed before developing into a fully functional male. Whilst old females may well develop a gonopodium but they dont have functional testicles with which to produce sperm.
While on the subject of sex, we may as well mention sperm. Guppies, in common with many other Poeciliids, can store sperm for many months. This means a female can produce brood after brood without every seeing another male. This having been said, they tend to use new sperm in poreference to old stored sperm. So, if you want to get babies from a female mated with a particular male, wait until she drops a brood of fry and place her with the male you want to father the next brood. He will do his duty and most of the fry from the next brood will be his.
Breeding guppies presents no real problem - they just do it all by themselves. Breeding good quality guppies, however, is a whole different ball game. Ideally you need a pair from the same strain to breed from. That way they will produce a brood of fry which closely resembles them. This, however, can be difficult to find because most shops have a tank of mixed males and another tank of females. Which male belongs to which female can be difficult to determine. While that might be a problem for the person wanting to breed show winners (they should buy their stock from a specialist breeder), the average aquarist need not be so picky. Unrelated fish will produce a wide selection of types within their offspring which can then be selected from to create a strain of guppy all of your own.
What you do need to look closely at is the body shape and carriage of the tail. Fish which have difficulty swimming properely are likely to pass this weakness on to their offspring. So look for fish with a deep caudal peduncle. They usually hold their tail much more upright and will still be able to swim properely when their finnage has developed to its maximum size.
Once you have your initial stock wait until the female has given birth once before saving your first brood. This is best done by carefully moving the gravid female into an aquarium with plenty of cover in it. Once she has given birth she should be moved back to the main aquarium and the fry reared up in the nursery tank.
This tank should be about 24” x 12” x 12” in size. Poor feeding, water quality or over crowding will all stunt young guppies. For this reason the fry should be fed 4 - 6 times a day using a mixture of live baby Brine shrimp and commercial fry foods. Water quality should be maintained by 20% water changes every other day and some form of gentle filtration. Over crowding is a problem which tends to creep up on you. As small fry a whole brood can be accommodated in a tank this size but latter you need to split them out in two or possibly three tanks. I usually do this as they become sexable with males being moved to their own tank so next generation I have virgin females to select from.
Average brood interval - 28 days
Average brood size - 30
Average age at sexual maturity - 3 months