Most people will not be able to tell what are the differences comparing between a normal lionhead with a ranchu but upon close observations, you can always tell them apart. The only notable characteristic that sets them different from each other is the arched back development and overall shape of the goldfish. Try to look closely and compare between the two pictures attached below and as you can see, the lionhead’s back is very much flat while the ranchu is more curved and that gives the latter a more rounded appearance. In terms of pricing and value, most people considered the ranchu's shape more pleasing towards their liking and thus, they usually command higher selling price.
Just like the ranchu, both are also hooded fish which means that it has a type of raspberry growth on its head that looks like clumps of jelly all lumped together. Surprisingly both fishes also do not have the dorsal fin unlike the other types of goldfish. In terms of size, ranchu are known to attain bigger belly and developed much bulkier weight while observations on the tail fin will tell you that the lionhead has one which is comparatively longer. Based on these characteristics you should be able to tell them apart with the arched back appearance to support and confirmed your view. In terms of appearance, both goldfish types also have striking color combination, and they can be found in typical orange, red, white and even all black on the whole body. These days, there is also the nacreous form which is basically a variety with speckled colored scales randomly distributed and appearing against a white background. Those are my favorite as they look absolutely cute and adorable.
The lionhead is believed to bring the Chinese good luck when the aquarium which has the fish in it is placed in a strategically right position in the house. As such, it is very common to see a very large aquarium specially made dedicated to this extraordinary and unique fish. Lionhead needs a very large living space to survive and live happily. Normally the minimum tank size for them should measure at least 50 gallons in capacity whereby a normal adult lionhead will actually grow to at least 10 inches in length when proper care is given. Just like all the other fancy goldfish varieties like the celestial, tosakin and bubble-eye, they are considered delicate species which are slow swimmers and most of the time will miss grabbing their foods. This is mainly due to the hooded growth which sometimes can covers their eyes and hinder their sight. When mixed with fast swimmers like normal torpedo-shaped common goldfish and oranda they will always lose out to food competition.
Chinese lionhead is very susceptible to different kinds of disease. One particular sickness that often attack this type of fish is the fluffy white colored fungus growth which can develop on the hood and degrade the tissue on it. Without treatment, it can spread and cause the skin to be engulfed. Fish infected with the disease will often lose appetite not wanting to eat and sometimes, they can still appear in their usual mood until the condition gets worse and starts to spread. Other than this, the flipover condition is also quite common and it is often related to overfeeding and the water quality that they lives in. This is identified to be related to infection affecting their swim bladder and I did wrote an article to discuss in details on the flipover disease and I would suggest you read up about this as it is very prevalent in every type of goldfish.
Aquarium tank in which your goldfish lives in should be best left barren with clear bottom without presence of gravel. Usually just like all the other types of goldfish, they can be very clumsy in their movement and the way they swim about. Aquarium decoration which sharp edges are known to cause injuries when the fish bump into it and there are instances when they might suffer bruises and cuts due to accidental scrapping onto the surface of the object. Plants might not be suitable in a goldfish tank because they are notorious of ripping the leaves apart and eating it when they become hungry (except for when you have water sprite). As such you will need a fast growing plant to cope up with their appetite. Thus based on these facts and argument, it is a matter of sacrificing viewing pleasure without any tank decoration in exchange for the safety of your pet fish. That is for you to decide.
Studying the difference between an Asagi and Shusui fish