By Courtney ShermanPeriod 3 Marine Biology

Mr. Dalke

Interactions Between Ecsenius bicolor and Gobiodon

okinawae

Taxonomy (Escenius bicolor)Animalia

ChordataActinopterygii

PerciformesBlenniidae

EsceniusE. bicolor

small and quirky tropical fishbodies are two colours: usually

orangey-yellow tail and a purplish-grey torso

originate in the Indo-Pacificvegetarian algae eaters known to perch on rocks and sandOn tops of heads: “cirri”

Bicolor Blennies

Taxonomy (Gobiodon okinawae)Animalia

ChordataActinopterygii

PerciformesGobiidae

GobiodonG. okinawae

known as "yellow clown gobies”found in the western pacific

(especially around Japan)smaller than many other gobieslive primarily in corals known to become aggressive towards

members of own species if in the same tank

keeps predators at bay with a slightly poisonous mucus that covers its skin

Okinawa Gobies

Pictureshttp://blennygobyinterractionscs.wiki.lovett.o

rg/

http://blennygobyinterractionscs.wiki.lovett.org/Images

Questions:1. Will any of the fish react to another fish (their own species or the other) in a benevolent manner?2. If aggression appears, will it be to a degree that requires the fish to be separated?3. Will genders be altered as a result of same species interaction?4. Will the fish already dwelling in the tanks permit for the new fish to encroach on their established territories?5. If there is conflict between the two species, which species will have the upper hand?

Hypothesis:

If a bicolor blenny or a Okinawa goby is introduced to a tank that already contains a bicolor blenny or a Okinawa goby, then

the relationship will be territorial and mildly defensive.

Answers:1. Will any of the fish react to another fish

(their own species or the other) in a benevolent manner?While the yellower watchmen gobies

were in tank 7, they seemed to have a very close relationship. The bicolor blenny in tank 5 did not appear to react in either way to the Okinawa gobies. The Okinawa gobies were not benevolent towards each other

Answers cont.2. If aggression appears, will it be to a

degree that requires the fish to be separated?

While there was aggression between the two Okinawa gobies, it was not to the extent to which they needed to be separated

Answers (cont.) 3. Will genders be altered as a result of same species interaction?While the blennies did not get the chance to

interact with each other, there was no mating and therefore little likelihood of gender change between the gobies

Answers cont.4. Will the fish already dwelling in the tanks permit for the new fish to encroach on their established territories?

The bicolor blenny in tank 5 appeared to have no problems with the introduction of the Okinawa gobies

Answers cont.5. If there is conflict between the two species, which species will have the upper hand?

There was no conflict between the two species; among the gobies, one was more aggressive than the other

ProjectObserving interactions between fish in tanks

5 and 8Shifting liverock around to see if loss of

perching places changes interactionsPlacing mildly territorial fish in same tank as

fellow species

Results: Bicolor Blenny Tank 5Bicolor Blenny of Tank 5 did not meet

hypothesisLittle/no reaction to Okinawa gobiesWas not able to see it interact with other

blenniesWhile it tends to perch in the same locations,

not aggressive over “territory”Most hyper fish in tank, particularly at

feeding time (afternoon)Did not use larger size against other fish

More Blenny Tank 5Tendency to bite at liverock/tank glass –

cleaner fish (algae)Most common perches are top of right

liverock (fall semester, before liverock shifted), and center liverock (after liverock shift)

Very hyper around feeding time

Results: Okinawa Gobies Tank 5One much more aggressive than

otherYes, more aggressive goby was

territorialMore aggressive goby hung out

more in right/center tankLess aggressive goby hung out more

in left tank/ on powerheadsAggressive goby took over non-

aggressor’s perchesLungingMore aggressive goby started pale

while the other was more yellow

More Okinawa GobiesPicked on goby fled to

overflow, secluded perches in tank

Video: http://blennygobyinterractionscs.wiki.lovett.org/Videos

Aggressive goby became fat and vibrant, while other became pale and thin

Hypothesis correct in this case

Results: Bicolor Blenny Tank 8Originally perched on cabbage coral, then

inside central and right caves of center piece of liverock

No interactions between blenny and Banggai Cardinalfish (tank mates)

Skittish at any activity outside tankImpossible to remove from cave(s)

Project ProblemsDeath of Cortez Redhead Goby at start of

yearDeaths of two yellow watchmen gobies

middle of fall semesterUnable to combine the two bicolor blennies

(impossible to catch)

Future SuggestionsContinue to watch aggression between yellow

Okinawa gobiesFind some way to combine the bicolor

blenniesHow would Okinawa gobies or bicolor

blennies interact with the shrimp in tank 7?Find a way to get the blenny in tank 8 to

emerge from liverock cavesWhat if gobies and blenny were in smaller

tank?

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