Roy doesn't always hit every note in the bass riff.
I've tabbed the whole riff (as it is played in the second verse)
together with the intro and interlude.
You may find Roy's guitar is tuned a little sharp. 

Capo on 3rd fret (sounding key F major)
Intro:
  D 
e|---------(2)--------2-2-----2-2-|--------2-2---------2-2-2-2-----|
B|---------(3)--------3-3-----3-3-|--------3-3-----3---3-3-3-3-----|
G|2-----------0h2---------0h2-----|---2--------2---------------0h2-|
D|----------------0---------------|0-------------------------------|
A|--------------------------------|--------------------------------|
E|--------------------------------|--------------------------------|
e|----2-2-----2-2-----2-------2-2-|
B|----3-3-----3-3-----3-------3-3-|
G|--------0h2---------2-----------|
D|0---------------0---------------|
A|--------------------------------|
E|--------------------------------|

Verse:
                                  (3rd string remains open)
e|----2-2-2-2-2-2-----2-2-----2-2-|----2-2-----2-2-----2-2-2-2-----|
B|----3-3-3-3-3-3-----3-3-----3-3-|----3-3-----3-3-----3-3-3-3-----|
G|2---------------4-------2-------|0------------------(0-0-0-0)----|
D|--------------------------------|--------4-------2-----------0---|
A|--------------------------------|--------------------------------|
E|--------------------------------|--------------------------------|
          Little  gold -  fish     in      your  bowl          I've   

                                   G                   >
e|----2-2-2-2---------2-2-----2-3-|--------3-3---------3-3-3-3-3-3-|
B|----3-3-3-3---------3-3-----3-3-|--------3-3---------3-3-3-3-3-3-|
G|---(0-0-0-0)-------(0-0)---(0-0)|--------0-0---------0-0-0-0-0-0-|
D|0h2---------4---2-------0-------|--------------------------------|
A|--------------------------------|----0h2-----0h2-----------------|
E|--------------------------------|3---------------3---------------|
  dug         you all     day      long.


e|----2-2-2-2---------2-2-----2-2-|----2-2-----2-2-----2-2-----2-2-|
B|----3-3-3-3---------3-3-----3-3-|----3-3-----3-3-----3-3-----3-3-|
G|0h2---------4---2-------0-------|---(0-0)---(0-0)---(0-0)----0-0-|
D|--------------------------------|4-------2-------0---------------|
A|--------------------------------|------------------------4-------|
E|--------------------------------|--------------------------------|

                                  (D)
e|----2-2-----2-2-----2-2-----2-2-|----2-2-2-2---------2-2-----2-2-|
B|----3-3-----3-3-----3-3-----3-3-|----3-3-3-3---------3-3-----3-3-|
G|----0-0-----0-0-----0-0-----0-0-|------------2-----------0h2-----|
D|--------------------------------|0---------------0---------------|
A|2-------0-------0h2-----4-------|--------------------------------|
E|--------------------------------|--------------------------------|
  cei -  lin'     of      my       song.
                                                       >
e|--------2-2---------2-2-----2-2-|----2-2-2-2---------2-----2-2-2-|
B|--------3-3-----3---3-3-----3-3-|----3-3-3-3---------3-----3-3-3-|
G|----2-------2-----------0h2-----|------------0h2-----2-----------|
D|0-------------------------------|0---------------0---------------|
A|--------------------------------|--------------------------------|
E|--------------------------------|--------------------------------|