Myxobolus cerebralis
... that different stages of the fish parasite Myxobolus cerebralis were originally thought to be three different organisms in two different classes?
... that different stages of the fish <a class="mw-redirect" href="./Parasite" id="mwBAk" rel="mw:WikiLink" title="Parasite">parasite</a> <i id="mwBAo"><b id="mwBAs"><a href="./Myxobolus_cerebralis" id="mwBAw" rel="mw:WikiLink" title="Myxobolus cerebralis">Myxobolus cerebralis</a></b></i> were originally thought to be three different organisms in two different <a href="./Class_(biology)" id="mwBA0" rel="mw:WikiLink" title="Class (biology)">classes</a>?