Don't use this plant if you've got gouramis. Mine grew very well until my three male dwarf gouramis decided that they were good nest material. I was left with stalks that eventually melted away.
I bought a wisteria bunched from a local shop and put it in my 160 litre Discus tank, with a pH of 6.7 and medium light. But within a week or so the stalks had gone hollow and the plant died, leaving a terrible mess on the aquarium floor. A friend bought the same species from the same store a few days after me, and hers was setting off new shoots and runners of all over her tank! So she gave me a series of cuttings from hers and I planted them, and voila! My tank is full of them! I don't know why it didn't do so well the first time, but 1 thing I have noticed is that they drop their leaves. I have one specimen that has a bare stalk and then a huge clump of leaves and shoots at the top! However, I highly recommend this plant for any tank as it is a superb grower and leaves a fantastic display!
Some of the above remarks seem to refer to a somewhat similar species known as water sprite (Ceratopteris thalictroides). The chief difference is that Wisteria is truly a stem plant, with leaves growing from a central stalk. Water Sprite has stemmed leaves that unroll from a central location. I have grown both and would definately recommend Wisteria. It is a wonderful starter plant and very easy to maintain. The somewhat similar looking Water Sprite can be a very beautiful plant, but very tough to maintain because of the new plants that develop on the leaves.
An interesting pattern I have noticed from my angel is that he will start to nibble at my water wisteria (Hygrophila difformis). But not just any part...he will only eat the baby leaves just at the top. So if you're looking to control the size of your water wisteria, I would definitely recommend you get an angel.
A beautiful but messy plant. This species of Hygro does well in medium to high light, likes a good diet of iron and CO2 and grows well in a fine grade gravel. It grows really well in my 55 L tank with a sand bottom. As other peaple have mentioned it does lose its leaves easily and makes a bit of a mess, but the leaves float and are easily removed. You also have to replant them often (I usually do mine once a month) by cutting the tops off, removing the bottom and replanting the tops. Overall, one of the easiest and attractive aquatic plants for the hobby.
I have this in a deep 125 liter with only 2x20 W bulbs and it is growing like crazy! I have both a planted bunch in my gravel and a floating bunch at the top, the floating bunch has much broader leaves, but they are both growing large and fast and offshooting dozens of roots. It has doubled it's size in only 6 weeks.