i do have to trim some of the faster-
growing plants like the hornwort (which died on me and has been replaced with wisteria and myrio) most of them i just break off the part that's too long and either replant it by just sticking it down in the substrait, or throw it in another tank, or throw it away entierly.
i do not fertilize right now, but i have very mineral rich water in my area, so they get a lot of nutrients already. i will be adding some fertilizer soon called "Flourish Excel" which adds carbon to the water without the use of CO2 injection, which can be expensive and messy.
i chose the fish because i liked them, and i knew they would not outgrow my tank. i hate the idea of buying a jeuvenile fish that will get too large for the tank with the idea that "I'll upgrade when it gets bigger" because something can always happen that keeps you from being able to upgrade the tank, and then you end up with a miserable, stunted, sick fish, and that's not fair.
when keeping live
plants, you have to keep in mind substrait, nutrients, and lighting. substrait should be deep, much deeper than you would keep it if you had no live
plants. its better to have a fine-textured substrait, such as small gravel, flourite, or sand. if you use sand, get some Malaysian trumpet snails. they do breed like crazy, but the spend all day burrowing through the substrait and keeping it aerated and fluffy, which the
plants like, and they keep toxic pockets of methane from forming and getting trapped under the sand.
nutrients, there are many fertilizers specifically made for aqariums that are safe for fish. the Flourish searies by seachem is great.
and for lighting, flourecent is better, because you get more wattage with less power usage and the light quality is better. you need to have 2 watts per gallon of water or more to grow most
plants. that means for a 10g tank, you'd need a 20 watt bulb, though its easier to get two 15 watt bulbs and just have 30 watts, which would be 3 watts per gallon.
there are some great forums for aquatic
plants, like Aquaria Central. try asking on there for some more advice.