During the first few weeks of life, puppies and kittens should nurse at least four to six times per day. Infrequent or weak nursing often signifies chilling, illness, or congenital problems and should be attended to immediately by a knowledgeable breeder or veterinarian. The two primary activities of all newborns are eating and sleeping. The eyes of puppies and kittens open between 10 and 16 days and their ears begin to function between 15 and 17 days after birth. Normal body temperature for puppies is 94 degrees Fahrenheit to 97 degrees Fahrenheit for the first two weeks of life. Normal kitten temperature during this time is about 95 degrees Fahrenheit. By 4 to 5 weeks of age, body temperatures have reached the normal adult temperature in both species (approximately 101.5 degrees Fahrenheit).

Because puppies and kittens have no shivering reflex for the first 6 days of life, an external heat source is necessary. The dam is the best source for this warmth. After 6 days, the puppies and kittens are able to shiver, but they are still very susceptible to chilling. Keeping the environment warm and free from drafts is of utmost importance during the first few weeks of life to prevent hypothermia. It is recommended that the environmental temperature be kept at 70 degrees Fahrenheit during this period, assuming the dam is providing an adequate amount of warmth and protection to the newborns.

Newborns should be weighed daily during the first 2 weeks and then every 3 to 4 days until weaning. A helpful guideline is for puppies to gain between 1 and 2 grams (g) per day for every pound of anticipated adult weight for the first 3 to 4 weeks of life. For example, if the anticipated adult weight of a dog is 25 pounds (lbs), the puppy should be gaining between 25 and 50 g/day (0.9 to 1.8 oz). Kittens usually weigh between 90 to 110 g at birth and should gain between 50 and 100 g (1.8 to 3.5 oz) per week until they are 5 to 6 months of age.

Although there is limited information available concerning milk intake in nursing puppies and kittens, one study reported that Beagle puppies consume between 160 and 175 g of milk per day. Naturally, puppies of larger breeds are expected to consume a greater volume of milk, with smaller breeds and kittens consuming less volume. Similarly, the volume of milk that a bitch produces varies with her size. German Shepherds produce about 900 g of milk per day in early lactation, with increases to a level of up to 1700 g/day during peak lactation. In contrast, a much smaller breed, the Dachshund, produces between 100 and 180 g/day in early lactation.

Other influences upon the volume of milk produced are litter size, age at which supplemental food is introduced, and age of weaning. In healthy puppies and kittens, the dam’s milk supports normal growth until puppies and kittens are approximately 4 weeks old. Supplemental feeding with commercial milk replacer should only be necessary with unusually large litters. After 4 weeks, milk alone no longer provides adequate calories or nutrients for continued normal development. At approximately the same time, puppies and kittens become increasingly interested in their environment and begin to spend more time awake and playing with each other. The time at which the dam’s milk is no longer solely able to meet the nutrient needs of the offspring corresponds to the time at which the young are becoming more interested in trying new foods.

Just when you think you have everything under control with your tanks, something is bound to go wrong. A mystery illness, occasional losses, lethargic fish, dull colours or slow growth are all signs that something is missing and your fish are not in as good a shape as they could be. Providing your fish with correct water conditions, regular feeding, and a suitably sized home are essential conditions for survival, but to get your fish to really thrive, you have to go the extra mile.

Environmental enrichment

A typical aquarium is a glass box with water, gravel, lights and a few ornaments. You could compare this to a room with a carpet, a sofa, and a coffee table; you could live in it, but its not much fun. What your fish need is the human equivalent of a Playstation, home cinema system, and a large garden with a trampoline. Environmental enrichment is giving your fish an environment with plenty of areas to keep them occupied, much like they would be in nature. This does not mean fluorescent ornaments, air powered divers, and plastic ‘mazes’ to confuse and trap your fish, but a more natural approach to aquascaping. Densely planted areas, surface cover, caves, quiet spots, and areas of flow are all natural components of an enriched aquarium. Individual species may have different requirements, but the majority of small aquarium fish will benefit from planted areas, scavengers such as small catfish and loaches will appreciate caves and hiding spots, and midwater ‘torpedo’ shaped fish will benefit from flowing water. Including as many of these components as possible will result in more diverse behaviour making your fish more interesting, livelier, healthier, and happier.

Feeding

I’ve heard rumours it is possible to survive on Guinness and potatoes, and although I enjoy an occasional pint of the Irish stout, I wouldn’t like to imagine what living off it might do to me. Quality branded foods provide all the essential ingredients your fish need to survive, but feeding a varied diet has plenty of other benefits. Treats, which are particularly enjoyable by many fish, can liven up your fish, and difficult to eat foods will make your fish work for their dinner, providing further environmental enrichment. For most fish, at least half of their diet should be made up from proprietary dried foods like flake, pellets, or crisps, which provide all the main staples and vitamins. Always use a known brand and avoid foods that are sold loose, since exposure to air, moisture, and light will all reduce a foods quality. To vary up your fishes diet try frozen foods or live foods and progress to occasional fresh foods. Grazers and algae eaters will enjoy most vegetables; slices of cucumber, courgette, shelled peas and lettuce are ideal. Most fish will nibble at fresh fruits and since we are all told to eat more fruit, I try and make a habit of eating soft fruits with stones or cores like mangos, plums, or pears and dropping the remains in my tanks for the fish to graze on for half an hour or so. Whilst a few other foods can be fed to fish, for safety it is best to stick to fresh fruits and vegetables.

Fasting

With a good varied diet, your fish will remain active and healthy, although a side effect is that they can become fussy eaters and may turn their nose up at more boring foods. This can be helpful because it will help to stop your fish from eating more than they need, but it may also mean they do not eat the dried foods which are more nutritionally balanced. A good solution is to have a day each week when your fish get no food at all. A fast day will ensure your fish are eager to feed on whatever they get given the next day, and they will also hunt the aquarium for leftovers (although with correct feeding levels there should be no leftover food) Fast days are only suitable for well established and healthy fish, which will cope for several days without feeding, and if they get used to regular days without food they will be fine if you have the occasional weekend away.

Set your day length

Fish have a body clock that prompts them when to carry out certain actions such as spawning, hunting, and resting. For the most part, this is set by the daily cycle of light and dark. If your fish are subjected to varying artificial day lengths by the lights being turned on and off at different times each day, their body clocks will be confused and they may begin to act unnaturally, becoming lethargic, timid, or boisterous. Setting your lights on timers will give a set period of light and dark which is the same each day. Your fish will then know when it is ‘lights on’ and ‘lights off’ time, reducing the shock of a sudden change in light and allowing their bodies to ‘plan’ their day.

Polish your water

Even with good filtration, chemical pollutants can build up in an aquarium over time resulting in a deteriation of health and often causing ‘mystery’ deaths. To prevent this, use activated carbon and/or ‘polishing’ medias such as polyfilters several times a year to remove any build-ups in the water. Many filters have carbon in them, and these need replacing on a regular basis if they are a permanent part of the filtration.

Avoid excessive treatments and chemicals

Many fish keepers fall into the trap of adding unnecessary treatments to the aquarium based on the instructions of manufacturers wishing to sell more products. Whilst the multitudes of available treatments, additives, and remedies available all have their uses, in an average established aquarium the only essential treatment is a water conditioner or dechlorinator to treat tap water. If you use anything else it should be for a specific reason and only for the time period needed for the problem to fix. Using chemical treatments as disease preventatives will put stress on your fish, and disease pathogens will become more resistant; using excessive fertilisers when plant problems may lie elsewhere will result in excess algae growth; using bacterial starters in mature tanks will result in fluctuations of waste pollutants.

Learn more

The best thing you can do to make sure your fish are as healthy as possible is to learn as much as you can about them. Whilst it is essential to find out the basics such as how big a fish gets, how peaceful it is, which fish it mixes with, and whether it has any unusual requirements before you purchase, it is equally useful to research your fish as much as possible once you have them in your tank. For instance, finding out about a fishes natural environment, what it feeds on, and how it lives can be invaluable to shape your aquarium to its needs. Researching will also uncover plenty of tips relating to specific fish, which might not come under the category of ‘general care’. Finding out that clay pots make ideal caves for Kribensis, that many suckermouth catfish need bogwood to graze on, or that some fish are over-sensitive to bright light are just examples of the items of knowledge you can gain by carrying out some proper research. Learning about your fish is part of the enjoyment of the hobby, and will allow you to appreciate your fish even more.

The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water.
Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.

Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.

In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous).

Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species appear to be born sexually mature, although they are not fully grown.

Some fishes are hermaphroditic, an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.

Successful reproduction and in many cases defense of the eggs and young is assured by rather stereotyped but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.

Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in gravel beds where they themselves hatched (anadromous fishes). Others undertake shorter migrations from lakes into streams or in other ways enter for spawning habitats that they do not ordinarily occupy.