harlequin rasbora Trigonostigma heteromorpha
-I have a school of 7 of these egg layers in my 60 gallon. They are great fish, very colorful and active. They do best in groups of 6 or more in a community to semi aggressive tank (as seen in the picture, with an angelfish). They should be kept in a well established tank, not put in a brand new tank. They stay small, usually about an inch long. They often show best in a planted tank but can easily be kept in non planted tanks. They eat well on flake foods and should be given the occasional live or frozen brine shrimp. While they prefer a lower pH they can be kept in higher pH (up to 7.8 that I know of) successfully. They just won't breed. Ideal temps are 74*f to 80*f.
neon tetra Paracheirodon innesi
-These little guys are very popular. They are another egg laying, schooling fish, best in groups of 6 or more and are good community fish. They are a bit delicate and should not be put into new tanks. In fact I find people are most successful with them in tanks that are at least 3 months or older. They stay small, usually staying about an inch long. They feed well on flake food and should be given live or frozen brine shrimp once in awhile. While they prefer lower pH water they do adapt. I know many people who keep them in a pH of 7.8 and with fairly hard water. Ideal temps are 76-82*f.
dalmatian sailfin molly Poecilia hybrid
-Dalmation sailfin mollies are a livebearing hybrid fish. Males have the sailfin and females do not. They get a bit large, up to 4 1/2 inches, and do best in bigger tanks (40 gallons or bigger IMO). Ideally they should be kept in groups of one male to several (2 or more) females. They can be a bit nippy at times and usually do well with larger peaceful to semi aggressive fish. They should be fed a diet high in plant matter, so alternating between regular flake food and a spirulina based food is a good idea. pH should be anywhere from 7.0 to 8.2 and temps can be from 72-80*f. Many people say they do better with some aquarium salt in the water at a level of a tsp per gallon or higher. They can even live in pure salt water. Some people have not had problems adding them to a new tank, others have.
mickey mouse platy, red platy, blue coral platy Xiphophorus sp./hybrids
-These are all various color varieties of platies. Their care is the same. Platies get about 2 inches in length and are robust. They are generally peaceful livebearing fish that usually do fine in both community and semi aggressive tanks. They should be fed a good flake food as well as an algae based flake food with the occasional live or frozen brine shrimp. They can be kept in tanks as small as 10 gallons. Generally they are best kept in groups of 1 male to 2 or more females. These are great starter fish as they come in a variety of colors and are hardy. They are adaptable to pH and hardness but prefer a pH from 7.0 to 8.0 and slightly hard water. They are very adaptable to temperature as well, anything from 65-80*F is fine with these guys as long as changes are made slowly.
lemon tetra Hyphessobrycon pulchripinnis
-These guys are another egg layer. They are fairly resilent little guys and do best in groups of 6 or more. They can be kept in community tanks but I wouldn't put them in with any long finned fish as I find them to be nippy. They feed well on flake food and should be given live or frozen brine once in awhile. They get about 2 inches long and can be kept in 20 gallon or bigger aquariums. While they prefer softer acidic water they can adapt to harder water with a higher pH (usually not higher than 7.8). Temperature range is 74-80*f. If something is wrong with the water they turn grey.
red tailed black shark Epalzeorhynchos bicolor (Labeo bicolor)
-These guys are a bit on the semi aggressive side, but usually only go after other bottom dwelling fish. I would not keep them in anything smaller than 30 gallons, also do not put more than 1 in a tank unless it is a large heavily planted aquarium. Also, do not put them with other fish that look similar to them. They get about 6 inches long and tend to stay near the bottom of the tank. They prefer nuetral to soft water but seem to be very adaptable. Preferred temps are 75-80*F. They will eat flake food and should be given live or frozen brine shrimp every now and then. They seem to be pretty hardy fish. Red tailed sharks are a bit shy so should be given several "hide outs" to make them feel secure enough to come out regularly.
Corydoras elegans/Corydoras panda
-Corydoras are very cute little catfish and there are many, many different species. They like to school and should be in groups of 3 or more. They don't neccessarly need to be kept with the same species though as different species will school together. Most corydoras stay an average of 2 inches in length give or take a little. They are often bought as scavengers for fish tanks but need to be fed as well. They should be fed a good quality, high protein sinking food as well as live or frozen blood worms and brine shrimp. Once or twice a week they should also be given algae wafers. They generally prefer softer pH and some are more adaptable than others. Usually if they are doing well at your LFS they will be fine in your home aquarium. They do fine in both community and semi aggressive tanks. Ideally the minimum size tank for all but the pygmy corys should be 10 gallons. They can be added once the tank has fully cycled (usually 6-8 weeks after it has been set up with fish in it).
Apistogramma sp
-There are several apistogramma species. Generally none really make good beginner fish because they are picky about water conditions. They are dwarf cichlids and despite being cichlids are usually peaceful. They do best and should be kept in soft water with a low pH. They are usually only successfuly kept in planted aquariums. They are micropredators, which means they need a high protein diet. While many will take flake food they usually will not do well on only that. Offering a variety of frozen and lives foods will be best for them. They like warmer water (upper 70's*f). They are usually kept in breeding pairs of one male and one female. They are usually best kept with tetras or smaller rasbora species. Single pairs can be kept in 10 gallon tanks. Water quality must be maintained with these sensitive little guys.
silver dollar family Metynnis
-These fish get BIG! They get to be as big as an average sized dinner plate. They also need to be in groups of 6 or more. Generally you can start them out in small tanks as they are usually available at 2 inches or so, but eventually you may need a tank of 90 gallons or bigger (probably bigger). They are very active and will often run into the side of the tank if spooked. Keeping them in groups helps calm them down a little. They love to eat plants, and should be fed a variety of vegetables as well as a good flake food. They prefer softer lower pH water but are adaptable. They can be kept with semi aggressive fish and even with many south american cichlids if the tank is big enough. They like water temps in the mid to upper 70's (*f). They are best added to an already cycled tank. They are fairly hardy as long as water quality is kept up and temperature does change to much. They tend to get ICH if the temperature flucuates.
botia striata
-These botias are a semi aggressive fish. They can be kept with bigger tetras (2"), most livebearers or semi aggressive fish but do not put them in with long finned fish. They are nippy. They usually get around 4 inches in length and do best in groups of 4 or more. They often "play" with each other. They should be fed a high protein sinking food along with frozen and/or live brine shrimp. A couple times a week they can be fed an algae wafer. They are very adaptable to water conditions as long as the water is clean and the temperature is stable. The temperature should not drop below 72*f or get above 84*f. Like all scaleless fish they are a little prone to getting ICH. I would not add them until the aquarium is fully cycled.
gold gourami Trichogaster trichopterus
-Gold gouramis are a color varient of the blue gourami and can get 4-6 inches long. They can be kept singly or one male with 2 or more females. They are semi aggressive and shouldn't be kept with very small fish. A singleton can be kept in a 30 gallon aquarium with other fish, if you want a group of gold gouramis I would recommend a bigger tank (55 gallons or more). They take flake food very well and should be given live or frozen brine shrimp as well. They are very hardy and very adaptable and make good beginner fish. Water temps should be 74-80*f. Keeping the water closer to 74*f sometimes keeps their aggression levels down.
honey gourami Trichogaster chuna
-Honey gouramis are small fish, usually staying around 2 inches in length. They can be kept singly or in groups of 1 male to 2 or more females. A single one with a few other small fish can be kept in tanks as small as 5 gallons. These gouramis are very peaceful and do best in community tanks. They are adaptable to water conditions as long as the water is clean and maintained. Temperature should be 74-80*f. They can be fed a good flake food but also need to be fed live or frozen brine and blood worms to keep looking their best. They may get a bit aggressive if they decide to breed as the male protects the nest and young.
pictus catfish Pimelodus pictus
-Pictus catfish are somewhat large (5") predatory fish. They should be kept in bigger semi aggressive tanks with fish that are near equal size or bigger. They prefer soft low pH water but do adapt to various conditions as long as they are not to extreme. They feed on almost anything they can fit in their mouths, from pellets and flake food to small fish. They will usually hide during the day if kept singly, so its usually best to keep 3 or more. They are best in bigger tanks because of their size (55 gallons or larger). Other than eating small fish they are not aggressive. Do not catch them with a net, use a cup to scoop them instead, because they have spines on their fines that will catch in the net. They are pretty hardy as long as the water quality is maintained (as with any fish).
Photo credits (in order of picture appearance):
Dystopian_Optimist, &_yo, Chrischang, Whisper Photography, Chrischang, Whisper Photography, Kasia/flickr