Java fern Microsorum pteropus

Seven sources and one number that contradicts another number. Aquarium Co-Op: almost any light will do, any range from low to medium-high light is perfect for this plant, and it will do best if provided with a 6700k spectrum bulb, but at the very high end range of light you can actually burn or melt it.

Aquarium Breeder: low to moderate, and low lighting is preferred. Aquarium Store Depot publishes a band in its own care box, low to moderate, 40 to 125 PAR, then tells you in the text to aim for about 60 to 125 PAR with a photoperiod of 6 to 10 hours per day.

Modest Fish states the opposite ceiling: java fern only requires low light, PAR under 50, though it adds that the plant tolerates more intense light and grows more quickly under brighter lights. Buce Plant says it thrives in low light and, when leaves are damaged, to reduce intensity or shorten the photoperiod to 6 to 8 hours per day.

Splashy Fish is the only source that puts the optimum above low: moderate lighting is optimal for java fern, it can tolerate low-light conditions but may grow slower. Wikipedia is the widest of all, that it can be cultivated in tap water, dim or bright light, with or without gravel.

Four of the seven state it and none of them asks for it. Aquarium Store Depot: CO2 requirement, no, and CO2 injection isn't really necessary for healthy java fern growth. Aquarium Breeder: not needed, and this is not really a necessity but if you want your fern to grow faster than normal then you definitely need to supply them with extra CO2.

Modest Fish: you don't need CO2 to grow java fern, of course it will grow quicker if you do use it. Buce Plant is the outlier in wording rather than in substance, giving CO2 requirement as not need, but always recommended.

Aquarium Co-Op and Splashy Fish do not raise the subject. On the silo's three way vocabulary this is beneficial, and it is the second plant record in a row where CO2 is optional.

Aquarium Store Depot: tank placement, midground and background. Aquarium Breeder gives mid to background and tells you to cultivate this plant in the center or at the back of the tank, adding that it can also be floated on the water surface.

Modest Fish gives mid to background. Splashy Fish puts it differently and says the same thing: unlike many aquarium plants that require planting on the substrate, java fern prefers to anchor itself to surfaces. Nothing here belongs in the foreground, and the height figures in station 09 are why.

This is the field the plant lives or dies by and six of the seven sources state it as a rule. Aquarium Store Depot is the blunt one: never bury the java fern rhizome in substrate, the rhizome must stay fully exposed and attached to hardscape, and once buried, the rhizome rots and the plant dies.

It calls burying the rhizome the number one mistake and adds, bury it in sand or gravel and it rots, every time. Aquarium Co-Op: the only thing to watch out for is that you don't bury the rhizome, the twig like portion of the plant, and if it is buried under gravel or sand it will rot.

It also states the plant does not require substrate, making java fern ideal for bare bottom tanks. Aquarium Breeder: one thing you should never do is burying the rhizomes down the substrate or it will rot.

Buce Plant: its rhizome must stay exposed, or the plant will rot. Splashy Fish: avoid burying the rhizome in the substrate, as this can lead to rot and hinder the plant's growth. Wikipedia gives the biology behind all five, that java ferns are epiphytes which attach to surfaces rather than rooting in substrate, and describes cultivation as tying or glueing the roots coming from the rhizome to rock or driftwood.

The seventh source, Modest Fish, is the one worth reading closely: everywhere you look, you'll see sources that tell you not to bury java fern down in the substrate because it will rot, in my experience, this is true and false, and then it states the same rule anyway, you don't want to bury the rhizomes down in the gravel, they will definitely rot over time. The nuance is roots against rhizome, not permission to plant it.

Aquarium Store Depot is the only source with a timescale: growth rate, slow, and under low to moderate light without CO2, a new leaf takes two to four weeks to fully develop. It also warns not to expect the tank to fill in within a few weeks.

Aquarium Co-Op and Modest Fish both give slow, and Aquarium Co-Op names the consequence: since this plant is such a slow grower, it can have terrible fights with algae. Aquarium Breeder and Buce Plant both give slow to moderate, and Buce Plant adds a diagnostic figure rather than a growth figure, that changes in light or nutrients might take up to two weeks to show results.

Aquarium Breeder is the one source that puts a lifespan on the plant, up to 2 years, and no other source here mentions one.

Two methods, and every source names at least one. Wikipedia: the plant will readily propagate asexually by producing small, adventitious plantlets from the leaf tips and margins, and the small sprouts quickly develop roots of their own.

Aquarium Co-Op: tiny java ferns are formed at the edge of the leaves, once they mature they drop off, and you can also break leaves off and let them float in the aquarium. It adds the emergency version, that if it starts to die it immediately produces new plantlets, sometimes as many as 20 babies per leaf.

Aquarium Store Depot names them correctly, adventitious plantlets, and gives the timing rule: wait until the plantlets have a few leaves and roots before you remove them from the parent plant. For the second method it says to divide the rhizome and always cut a section that has some roots, and preferably some leaves as well.

Aquarium Breeder gives both, splitting the rhizomes into desired sizes and the plantlets on the leaf tips. Modest Fish sums up what all of them describe: frankly, it usually does a great job of propagating itself.

Four bands, no two identical, and 72 to 82 is the only span all four contain. Aquarium Breeder gives 68 to 82 °F, 20 to 28 C, as preferred. Aquarium Store Depot gives 64 to 82 °F, 18 to 28 C, which is the widest here.

Splashy Fish gives 72 to 82 °F, 22 to 28 C. Modest Fish gives 70 to 83 °F as ideal. Aquarium Co-Op publishes no temperature at all and describes the tolerance instead, from soft acidic water to alkaline conditions, and even brackish tanks.

Three sources give 6.0 to 8.0 and one gives 6.0 to 7.5, so the row prints the span all four contain. Aquarium Breeder: 6.0 to 8.0, and it is known to tolerate a wide pH range. Aquarium Store Depot: 6.0 to 8.0, and they do prefer soft acidic water but will do just fine in slightly alkaline conditions too.

Modest Fish: 6.0 to 8.0. Splashy Fish: it generally thrives in slightly acidic to neutral water with a pH between 6.0 and 7.5. On hardness the three sources that publish a figure all publish the same one and all publish it in the wrong unit for comparing against our animal records: 2 to 15 dKH, which is carbonate hardness rather than the general hardness those records carry.

Modest Fish converts it to 33.3 to 250.1 ppm. Aquarium Breeder describes the tolerance in words as well, soft to moderately hard water, can thrive in hard water also.

The field this plant is bought for, and the first field on any plant record here where the sources agree. Aquarium Co-Op: most fish do not like the taste of java fern, so even many plant eating fish will not eat it, and the leaves are also very thick and rugged, they can take a beating from a large cichlid or some goldfish who just like to play with them.

Aquarium Store Depot gives the mechanism: java fern foliage contains some chemicals that taste bad for plant-eating fish, which means they are one of the few safe options for keeping with almost all tropical fish, and it names betta fish, plecos, rasboras, danios, tetras, cherry barbs, corydoras, goldfish, small cichlids and otos. Aquarium Breeder: it is hardy and tough which makes it difficult for herbivorous, nippy fishes to feed on them, and java fern can withstand aggression from cichlids, oscar, goldfish species that normally eat aquatic plants, they find java fern to be unappetizing due to their hard leaves.

Buce Plant: its tough leaves can handle grazing fish like goldfish or cichlids. Modest Fish agrees and then breaks the pattern with its own tank: apparently it's not very tasty, this is a good thing, and a lot of herbivorous fish like plecos won't completely destroy your ferns to eat them, but I had a very large green severum that did destroy and eat the java fern.

Two sources name animals to avoid: Aquarium Breeder says to avoid keeping them with large species of crayfish as they are known to destroy the plant, and Aquarium Store Depot says large predator fish and aggressive New World cichlid types should also be avoided, and that mature plants are usually fine with African cichlids while young growth and young plants might still take some damage. Splashy Fish is the only source that calls the leaves delicate rather than tough, and the only one to warn off a small fish: avoid tiger barbs and other fin-nipping varieties, as they might damage the delicate leaves of java fern.

Wikipedia adds the invertebrate half, that it is more snail resistant and grows better with higher fish loads, and Aquarium Breeder names it one of the best plants for shrimp tanks and snails, listing cherry shrimp, ghost shrimp, amano shrimp, ramshorn, nerite, Malaysian trumpet and mystery snails. Added with our rabbit snail record: two of that record’s six sources say rabbit snails are not really interested in eating plants except java ferns, which they like to feast on.

One of those two is Aquarium Breeder, which is also one of the five sources above, and on this plant it names java fern one of the best plants for shrimp tanks and snails while listing cherry shrimp, ghost shrimp, amano shrimp, ramshorn, nerite, Malaysian trumpet and mystery snails. Both statements can stand, since that list does not include this snail, but the water makes it a live question: this record runs 72 to 82 °F and the rabbit snail record 78 to 84, so they overlap from 78 to 82.